WorldWideScience

Sample records for atlantic north america

  1. A detailed gravimetric geoid of North America, the North Atlantic, Eurasia, and Australia

    Science.gov (United States)

    Marsh, J. G.

    1973-01-01

    A computer program was developed for the calculation of a goid based upon a combination of satellite and surface gravity data. A detailed gravimetric geoid of North America, the North Atlantic, Eurasia, and Australia was derived by using this program.

  2. Extreme conditions over Europe and North America: role of the Atlantic Multidecadal Variability

    Science.gov (United States)

    Ruprich-Robert, Yohan; Msadek, Rym; Delworth, Tom

    2016-04-01

    The Atlantic Multidecadal Variability (AMV) is the result and possibly the source of marked modulations of the climate over many areas of the globe. For instance, the relatively warm and dry climate of North America throughout the 30-yr interval of 1931-60, during which the Dust Bowl and the 1950's drought occurred, has been linked to the concomitant warm phase of the AMV. During this period relative warm and wet conditions prevailed over Europe. After 1960, the Atlantic began to cool, and for almost three decades the North American climate turned wetter and cooler whereas Europe experienced cooler and dryer conditions. However, the shortness of the historical observations compared to the AMV period suggested by longer proxy (~60-80yr) does not allow to firmly conclude on the causal effect of the AMV. We use a model approach to isolate the causal role of the AMV on the occurrence of extreme events over Europe and North America. We present experiments based on two GFDL global climate models, a low resolution version, CM2.1 and a higher resolution model for the atmospheric component, FLOR. In both model experiments sea surface temperatures in the North Atlantic sector are restored to the observed AMV pattern, while the other basins are left fully coupled. In order to explore and robustly isolate the AMV impacts on extreme events, we use large ensemble simulations (100 members for CM2.1 and 50 for FLOR) that we run for 20 years. We find that a positive phase of the AMV increases the frequency of occurrence of drought over North America and of extremely cold/warm conditions over Northern/Central Europe during winter/summer. Interestingly, we find that the AMV impacts on these extreme conditions are modulated by the Pacific response to the AMV itself. Members that develop a weak Pacific response show more extreme events over Europe whereas those that develop a strong Pacific response show more extreme events over North America.

  3. Impact of North America on the aerosol composition in the North Atlantic free troposphere

    Directory of Open Access Journals (Sweden)

    M. I. García

    2017-06-01

    Full Text Available In the AEROATLAN project we study the composition of aerosols collected over  ∼  5 years at Izaña Observatory (located at  ∼  2400 m a.s.l. in Tenerife, the Canary Islands under the prevailing westerly airflows typical of the North Atlantic free troposphere at subtropical latitudes and midlatitudes. Mass concentrations of sub-10 µm aerosols (PM10 carried by westerly winds to Izaña, after transatlantic transport, are typically within the range 1.2 and 4.2 µg m−3 (20th and 80th percentiles. The main contributors to background levels of aerosols (PM10 within the 1st–50th percentiles  =  0.15–2.54 µg m−3 are North American dust (53 %, non-sea-salt sulfate (14 % and organic matter (18 %. High PM10 events (75th–95th percentiles  ≈  4.0–9.0 µg m−3 are prompted by dust (56 %, organic matter (24 % and non-sea-salt sulfate (9 %. These aerosol components experience a seasonal evolution explained by (i their spatial distribution in North America and (ii the seasonal shift of the North American outflow, which migrates from low latitudes in winter (∼  32° N, January–March to high latitudes in summer (∼  52° N, August–September. The westerlies carry maximum loads of non-sea-salt sulfate, ammonium and organic matter in spring (March–May, of North American dust from midwinter to mid-spring (February–May and of elemental carbon in summer (August–September. Our results suggest that a significant fraction of organic aerosols may be linked to sources other than combustion (e.g. biogenic; further studies are necessary for this topic. The present study suggests that long-term evolution of the aerosol composition in the North Atlantic free troposphere will be influenced by air quality policies and the use of soils (potential dust emitter in North America.

  4. Geophysical and geodynamic studies of the North Atlantic Realm

    DEFF Research Database (Denmark)

    Schiffer, Christian

    2015-01-01

    The geology of the North Atlantic Realm (NAR), including the North Atlantic, Greenland, the Arctic, Iceland, Scandinavia, Northern Europe and Northeast America has been studied for more than a century and inspired some of the most fundamental theories in geoscience, such as plate tectonics, the s...

  5. The influence of boreal biomass burning emissions on the distribution of tropospheric ozone over North America and the North Atlantic during 2010

    OpenAIRE

    M. Parrington; P. I. Palmer; D. K. Henze; D. W. Tarasick; E. J. Hyer; R. C. Owen; D. Helmig; C. Clerbaux; K. W. Bowman; M. N. Deeter; E. M. Barratt; P.-F. Coheur; D. Hurtmans; M. George; J. R. Worden

    2011-01-01

    We analyse the tropospheric ozone distribution over North America and the North Atlantic to boreal biomass burning emissions during the summer of 2010 using the GEOS-Chem 3-D global tropospheric chemical transport model, and observations from in situ and satellite instruments. In comparison to observations from the PICO-NARE observatory in the Azores, ozonesondes across Canada, and the Tropospheric Emission Spectrometer (TES) and Infrared Atmospheric Sounding Instrument (IASI) satellite instr...

  6. Synoptic Scale North American Weather Tracks and the Formation of North Atlantic Windstorms

    Science.gov (United States)

    Baum, A. J.; Godek, M. L.

    2014-12-01

    Each winter, dozens of fatalities occur when intense North Atlantic windstorms impact Western Europe. Forecasting the tracks of these storms in the short term is often problematic, but long term forecasts provide an even greater challenge. Improved prediction necessitates the ability to identify these low pressure areas at formation and understand commonalities that distinguish these storms from other systems crossing the Atlantic, such as where they develop. There is some evidence that indicates the majority of intense windstorms that reach Europe have origins far west, as low pressure systems that develop over the North American continent. This project aims to identify the specific cyclogenesis regions in North America that produce a significantly greater number of dangerous storms. NOAA Ocean Prediction Center surface pressure reanalysis maps are used to examine the tracks of storms. Strong windstorms are characterized by those with a central pressure of less than 965 hPa at any point in their life cycle. Tracks are recorded using a coding system based on source region, storm track and dissipation region. The codes are analyzed to determine which region contains the most statistical significance with respect to strong Atlantic windstorm generation. The resultant set of codes also serves as a climatology of North Atlantic extratropical cyclones. Results indicate that a number of windstorms favor cyclogenesis regions off the east coast of the United States. A large number of strong storms that encounter east coast cyclogenesis zones originate in the central mountain region, around Colorado. These storms follow a path that exits North America around New England and subsequently travel along the Canadian coast. Some of these are then primed to become "bombs" over the open Atlantic Ocean.

  7. Tropical North Atlantic ocean-atmosphere interactions synchronize forest carbon losses from hurricanes and Amazon fires

    Science.gov (United States)

    Chen, Yang; Randerson, James T.; Morton, Douglas C.

    2015-08-01

    We describe a climate mode synchronizing forest carbon losses from North and South America by analyzing time series of tropical North Atlantic sea surface temperatures (SSTs), landfall hurricanes and tropical storms, and Amazon fires during 1995-2013. Years with anomalously high tropical North Atlantic SSTs during March-June were often followed by a more active hurricane season and a larger number of satellite-detected fires in the southern Amazon during June-November. The relationship between North Atlantic tropical cyclones and southern Amazon fires (r = 0.61, p forests.

  8. Contingent Pacific-Atlantic Ocean influence on multicentury wildfire synchrony over western North America.

    Science.gov (United States)

    Kitzberger, Thomas; Brown, Peter M; Heyerdahl, Emily K; Swetnam, Thomas W; Veblen, Thomas T

    2007-01-09

    Widespread synchronous wildfires driven by climatic variation, such as those that swept western North America during 1996, 2000, and 2002, can result in major environmental and societal impacts. Understanding relationships between continental-scale patterns of drought and modes of sea surface temperatures (SSTs) such as El Niño-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and Atlantic Multidecadal Oscillation (AMO) may explain how interannual to multidecadal variability in SSTs drives fire at continental scales. We used local wildfire chronologies reconstructed from fire scars on tree rings across western North America and independent reconstructions of SST developed from tree-ring widths at other sites to examine the relationships of multicentury patterns of climate and fire synchrony. From 33,039 annually resolved fire-scar dates at 238 sites (the largest paleofire record yet assembled), we examined forest fires at regional and subcontinental scales. Since 1550 CE, drought and forest fires covaried across the West, but in a manner contingent on SST modes. During certain phases of ENSO and PDO, fire was synchronous within broad subregions and sometimes asynchronous among those regions. In contrast, fires were most commonly synchronous across the West during warm phases of the AMO. ENSO and PDO were the main drivers of high-frequency variation in fire (interannual to decadal), whereas the AMO conditionally changed the strength and spatial influence of ENSO and PDO on wildfire occurrence at multidecadal scales. A current warming trend in AMO suggests that we may expect an increase in widespread, synchronous fires across the western U.S. in coming decades.

  9. Tropical North Atlantic ocean-atmosphere interactions synchronize forest carbon losses from hurricanes and Amazon fires

    OpenAIRE

    Chen, Y; Randerson, JT; Morton, DC

    2015-01-01

    ©2015. American Geophysical Union. All Rights Reserved. We describe a climate mode synchronizing forest carbon losses from North and South America by analyzing time series of tropical North Atlantic sea surface temperatures (SSTs), landfall hurricanes and tropical storms, and Amazon fires during 1995-2013. Years with anomalously high tropical North Atlantic SSTs during March-June were often followed by a more active hurricane season and a larger number of satellite-detected fires in the south...

  10. Seasonal influence of ENSO on the Atlantic ITCZ and equatorial South America

    Science.gov (United States)

    Münnich, M.; Neelin, J. D.

    2005-11-01

    In late boreal spring, especially May, a strong relationship exists in observations among precipitation anomalies over equatorial South America and the Atlantic intertropical convergence zone (ITCZ), and eastern equatorial Pacific and central equatorial Atlantic sea surface temperature anomalies (SSTA). A chain of correlations of equatorial Pacific SSTA, western equatorial Atlantic wind stress (WEA), equatorial Atlantic SSTA, sea surface height, and precipitation supports a causal chain in which El Niño/Southern Oscillation (ENSO) induces WEA stress anomalies, which in turn affect Atlantic equatorial ocean dynamics. These correlations show strong seasonality, apparently arising within the atmospheric links of the chain. This pathway and the influence of equatorial Atlantic SSTA on South American rainfall in May appear independent of that of the northern tropical Atlantic. Brazil's Nordeste is affected by the northern tropical Atlantic. The equatorial influence lies further to the north over the eastern Amazon and the Guiana Highlands.

  11. Post-1980 shifts in the sensitivity of boreal tree growth to North Atlantic Ocean dynamics and seasonal climate. Tree growth responses to North Atlantic Ocean dynamics

    Science.gov (United States)

    Ols, Clémentine; Trouet, Valerie; Girardin, Martin P.; Hofgaard, Annika; Bergeron, Yves; Drobyshev, Igor

    2018-06-01

    The mid-20th century changes in North Atlantic Ocean dynamics, e.g. slow-down of the Atlantic meridional overturning thermohaline circulation (AMOC), have been considered as early signs of tipping points in the Earth climate system. We hypothesized that these changes have significantly altered boreal forest growth dynamics in northeastern North America (NA) and northern Europe (NE), two areas geographically adjacent to the North Atlantic Ocean. To test our hypothesis, we investigated tree growth responses to seasonal large-scale oceanic and atmospheric indices (the AMOC, North Atlantic Oscillation (NAO), and Arctic Oscillation (AO)) and climate (temperature and precipitation) from 1950 onwards, both at the regional and local levels. We developed a network of 6876 black spruce (NA) and 14437 Norway spruce (NE) tree-ring width series, extracted from forest inventory databases. Analyses revealed post-1980 shifts from insignificant to significant tree growth responses to summer oceanic and atmospheric dynamics both in NA (negative responses to NAO and AO indices) and NE (positive response to NAO and AMOC indices). The strength and sign of these responses varied, however, through space with stronger responses in western and central boreal Quebec and in central and northern boreal Sweden, and across scales with stronger responses at the regional level than at the local level. Emerging post-1980 associations with North Atlantic Ocean dynamics synchronized with stronger tree growth responses to local seasonal climate, particularly to winter temperatures. Our results suggest that ongoing and future anomalies in oceanic and atmospheric dynamics may impact forest growth and carbon sequestration to a greater extent than previously thought. Cross-scale differences in responses to North Atlantic Ocean dynamics highlight complex interplays in the effects of local climate and ocean-atmosphere dynamics on tree growth processes and advocate for the use of different spatial scales in

  12. Assessing the role of North Atlantic freshwater forcing in millennial scale climate variability: a tropical Atlantic perspective

    Energy Technology Data Exchange (ETDEWEB)

    Dahl, Kristina A [Massachusetts Institute of Technology/Woods Hole Oceanographic Institution Joint Program, Woods Hole, MA (United States); Broccoli, Anthony J [Rutgers University, Department of Environmental Sciences, New Brunswick, NJ (United States); Stouffer, Ronald J [Geophysical Fluid Dynamics Laboratory, Princeton, NJ (United States)

    2005-03-01

    This study analyzes a three-member ensemble of experiments, in which 0.1 Sv of freshwater was applied to the North Atlantic for 100 years in order to address the potential for large freshwater inputs in the North Atlantic to drive abrupt climate change. The model used is the GFDL R30 coupled ocean-atmosphere general circulation model. We focus in particular on the effects of this forcing on the tropical Atlantic region, which has been studied extensively by paleoclimatologists. In response to the freshwater forcing, North Atlantic meridional overturning circulation is reduced to roughly 40% by the end of the 100 year freshwater pulse. Consequently, the North Atlantic region cools by up to 8 C. The extreme cooling of the North Atlantic increases the pole-to-equator temperature gradient and requires more heat be provided to the high latitude Atlantic from the tropical Atlantic. To accommodate the increased heat requirement, the ITCZ shifts southward to allow for greater heat transport across the equator. Accompanying this southward ITCZ shift, the Northeast trade winds strengthen and precipitation patterns throughout the tropical Atlantic are altered. Specifically, precipitation in Northeast Brazil increases, and precipitation in Africa decreases slightly. In addition, we find that surface air temperatures warm over the tropical Atlantic and over Africa, but cool over northern South America. Sea-surface temperatures in the tropical Atlantic warm slightly with larger warm anomalies developing in the thermocline. These responses are robust for each member of the ensemble, and have now been identified by a number of freshwater forcing studies using coupled OAGCMs. The model responses to freshwater forcing are generally smaller in magnitude, but have the same direction, as paleoclimate data from the Younger Dryas suggest. In certain cases, however, the model responses and the paleoclimate data directly contradict one another. Discrepancies between the model simulations

  13. Ocean deformation processes at the Caribbean-North America-South America triple junction: Initial results of the 2007 ANTIPLAC marine survey

    Science.gov (United States)

    Benard, F.; Deville, E.; Le Drezen, E.; Loubrieu, B.; Maltese, L.; Patriat, M.; Roest, W.; Thereau, E.; Umber, M.; Vially, R.

    2007-12-01

    Marine geophysical data (multibeam and seismic lines) acquired in 2007 (ANTIPLAC survey) in the North-South Americas-Caribbean triple point (Central Atlantic, Barracuda and Tiburon ridges area), provide information about the structure, the tectonic processes and the timing of the deformation in this large diffuse zone of polyphase deformation. The deformation of the plate boundary between the north and south Americas is distributed on several structures located in the Atlantic plain, at the front of the Barbados accretionary prism. In this area of deformation of the Atlantic oceanic lithosphere, the main depressions and transform troughs are filled by Late Pliocene-Pleistocene turbidite sediments, especially in the Barracuda trough, north of Barracuda ridge. These sediments are not issued from the Lesser Antilles volcanic arc but they are sourced from the East, probably by the Orinoco turbidite distal system, through channels transiting in the Atlantic abyssal plain. These Late Pliocene- Quaternary sediments show locally spectacular evidences of syntectonic deformation. It can be shown notably that Barracuda ridge includes a pre-existing transform fault system which has been folded and uplifted very recently during Pleistocene times. This recent deformation has generate relieves up to 2 km high with associated erosion processes notably along the northern flank the Barracuda ridge. The subduction of these recently deformed ridges induces deformation of earlier structures within the Barbados accretionary prism. These asperities within the Atlantic oceanic lithosphere which is subducted in the Lesser Antilles active margin are correlated with the zone of intense seismic activity below the volcanic arc.

  14. Rotational atmospheric circulation during North Atlantic-European winter: the influence of ENSO

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Serrano, J. [UCM, Departamento de Geofisica y Meteorologia, Madrid (Spain); Institut Catala de Ciencies del Clima (IC3), Barcelona (Spain); Rodriguez-Fonseca, B.; Zurita-Gotor, P.; Camara, A. de la [UCM, Departamento de Geofisica y Meteorologia, Madrid (Spain); Blade, I. [UB, Departament d' Astronomia i Meteorologia, Barcelona (Spain)

    2011-11-15

    The dominant variability modes of the North Atlantic-European rotational flow are examined by applying a principal component analysis (PCA/EOF) to the 200 hPa streamfunction mid-winter anomalies (Jan-Feb monthly means). The results reveal that, when this norm is used, the leading mode (EOF1) does not correspond to the traditional North Atlantic Oscillation (NAO, which appears in our analysis as the second leading mode, EOF2) but is the local manifestation of the leading hemispheric streamfunction EOF. The regression of this regional mode onto the global SST field exhibits a clear El Nino signature, with no signal over the Atlantic, while the associated upper height anomalies resemble the Tropical/Northern Hemisphere (TNH) pattern. East of North America, this TNH-like wavetrain produces a meridional dipole-like pattern at lower levels. Although in some ways this pattern resembles the NAO (EOF2), the dynamics of these two modes are very different in that only EOF2 is associated with a latitudinal shift of the North Atlantic stormtrack. Thus, the choice of the streamfunction norm in the EOF analysis allows the separation of two different phenomena that can produce similar dipolar surface pressure anomalies over the North Atlantic but that have different impact on European climate. These two modes also differ on their contribution to variability at lower levels: while NAO-EOF2 is mostly confined to the North Atlantic, TNH-EOF1 has a more annular, global character. At upper levels NAO-EOF2 also produces a global pattern but with no annular structure, reminiscent of the ''circumglobal'' teleconnection. (orig.)

  15. The Atlantic Basin: A New Africa-Americas Oil and Gas Geopolitical Arena

    International Nuclear Information System (INIS)

    Auge, Benjamin

    2014-01-01

    The Atlantic Ocean (North and Latin America, Africa and Europe) is bordered by states experiencing a significant change in their relationships regarding hydrocarbons. The rapid development of shale oil and gas in USA allows the country more and more independence from African states in the gulf of Guinea. Some of these producing countries like Nigeria are worried that the special political and security ties with America will turn into a mere trade relationship. Africa's excess oil and gas capacity, no longer sold to USA, is bought by Latin America and Europe (alongside countries such as India). Oil and gas transactions are creating new networks and fresh ties between countries from these zones that previously had to do with each other. From a geological perspective, the Atlantic Ocean is bordered by coastal countries with multiple similarities, and which we will refer to as the Atlantic basin. Millions of years back, they formed one single continent. Oil companies, bearing this geological similarity in mind and profiting from better technology, apply for oil blocks on one side of the Atlantic basin whenever a discovery is made on the opposite side. New relationships are thus flourishing between Latin-American and African states. New players, competing to control new zones, gives rise to a fresh geopolitical situation that we are going to examine in this article

  16. How does dynamical downscaling affect model biases and future projections of explosive extratropical cyclones along North America's Atlantic coast?

    Science.gov (United States)

    Seiler, C.; Zwiers, F. W.; Hodges, K. I.; Scinocca, J. F.

    2018-01-01

    Explosive extratropical cyclones (EETCs) are rapidly intensifying low pressure systems that generate severe weather along North America's Atlantic coast. Global climate models (GCMs) tend to simulate too few EETCs, perhaps partly due to their coarse horizontal resolution and poorly resolved moist diabatic processes. This study explores whether dynamical downscaling can reduce EETC frequency biases, and whether this affects future projections of storms along North America's Atlantic coast. A regional climate model (CanRCM4) is forced with the CanESM2 GCM for the periods 1981 to 2000 and 2081 to 2100. EETCs are tracked from relative vorticity using an objective feature tracking algorithm. CanESM2 simulates 38% fewer EETC tracks compared to reanalysis data, which is consistent with a negative Eady growth rate bias (-0.1 day^{-1}). Downscaling CanESM2 with CanRCM4 increases EETC frequency by one third, which reduces the frequency bias to -22%, and increases maximum EETC precipitation by 22%. Anthropogenic greenhouse gas forcing is projected to decrease EETC frequency (-15%, -18%) and Eady growth rate (-0.2 day^{-1}, -0.2 day^{-1}), and increase maximum EETC precipitation (46%, 52%) in CanESM2 and CanRCM4, respectively. The limited effect of dynamical downscaling on EETC frequency projections is consistent with the lack of impact on the maximum Eady growth rate. The coarse spatial resolution of GCMs presents an important limitation for simulating extreme ETCs, but Eady growth rate biases are likely just as relevant. Further bias reductions could be achieved by addressing processes that lead to an underestimation of lower tropospheric meridional temperature gradients.

  17. The roles of static stability and tropical-extratropical interactions in the summer interannual variability of the North Atlantic sector

    Science.gov (United States)

    Mbengue, Cheikh Oumar; Woollings, Tim; Dacre, Helen F.; Hodges, Kevin I.

    2018-04-01

    Summer seasonal forecast skill in the North Atlantic sector is lower than winter skill. To identify potential controls on predictability, the sensitivity of North Atlantic baroclinicity to atmospheric drivers is quantified. Using ERA-INTERIM reanalysis data, North Atlantic storm-track baroclinicity is shown to be less sensitive to meridional temperature-gradient variability in summer. Static stability shapes the sector's interannual variability by modulating the sensitivity of baroclinicity to variations in meridional temperature gradients and tropopause height and by modifying the baroclinicity itself. High static stability anomalies at upper levels result in more zonal extratropical cyclone tracks and higher eddy kinetic energy over the British Isles in the summertime. These static stability anomalies are not strongly related to the summer NAO; but they are correlated with the suppression of convection over the tropical Atlantic and with a poleward-shifted subtropical jet. These results suggest a non-local driver of North Atlantic variability. Furthermore, they imply that improved representations of convection over the south-eastern part of North America and the tropical Atlantic might improve summer seasonal forecast skill.

  18. Moisture transport from the Atlantic to the Pacific basin and its response to North Atlantic cooling and global warming

    Energy Technology Data Exchange (ETDEWEB)

    Richter, Ingo [University of Hawaii at Manoa, International Pacific Research Center, Honolulu, HI (United States); Xie, Shang-Ping [University of Hawaii at Manoa, Department of Meteorology, Honolulu, HI (United States)

    2010-08-15

    Atmospheric moisture transport from the Atlantic to the Pacific basin plays an important role in regulating North Atlantic salinity and thus the strength of the thermohaline circulation. Potential changes in the strength of this moisture transport are investigated for two different climate-change scenarios: North Atlantic cooling representative of Heinrich events, and increased greenhouse gas (GHG) forcing. The effect of North Atlantic cooling is studied using a coupled regional model with comparatively high resolution that successfully simulates Central American gap winds and other important aspects of the region. Cooler North Atlantic sea surface temperature (SST) in this model leads to a regional decrease of atmospheric moisture but also to an increase in wind speed across Central America via an anomalous pressure gradient. The latter effect dominates, resulting in a 0.13 Sv (1 Sv = 10{sup 6} m{sup 3} s{sup -1}) increase in overall moisture transport to the Pacific basin. In fresh water forcing simulations with four different general circulation models, the wind speed effect is also present but not strong enough to completely offset the effect of moisture decrease except in one model. The influence of GHG forcing is studied using simulations from the Intergovernmental Panel on Climate Change archive. In these simulations atmospheric moisture increases globally, resulting in an increase of moisture transport by 0.25 Sv from the Atlantic to Pacific. Thus, in both scenarios, moisture transport changes act to stabilize the thermohaline circulation. The notion that the Andes effectively block moisture transport from the Atlantic to the Pacific basin is not supported by the simulations and atmospheric reanalyses examined here. This indicates that such a blocking effect does not exist or else that higher resolution is needed to adequately represent the steep orography of the Andes. (orig.)

  19. Assessment of atmospheric processes driving ozone variations in the subtropical North Atlantic free troposphere

    Directory of Open Access Journals (Sweden)

    E. Cuevas

    2013-02-01

    Full Text Available An analysis of the 22-yr ozone (O3 series (1988–2009 at the subtropical high mountain Izaña~station (IZO; 2373 m a.s.l., representative of free troposphere (FT conditions, is presented. Diurnal and seasonal O3 variations as well as the O3 trend (0.19 ± 0.05 % yr−1 or 0.09 ppbv yr−1, are assessed. A climatology of O3 transport pathways using backward trajectories shows that higher O3 values are associated with air masses travelling above 4 km altitude from North America and North Atlantic Ocean, while low O3 is transported from the Saharan continental boundary layer (CBL. O3 data have been compared with PM10, 210Pb, 7Be, potential vorticity (PV and carbon monoxide (CO. A clear negative logarithmic relationship was observed between PM10 and surface O3 for all seasons. A similar relationship was found between O3 and 210Pb. The highest daily O3 values (90th percentile are observed in spring and in the first half of summer time. A positive correlation between O3 and PV, and between O3 and 7Be is found throughout the year, indicating that relatively high surface O3 values at IZO originate from the middle and upper troposphere. We find a good correlation between O3 and CO in winter, supporting the hypothesis of long-range transport of photochemically generated O3 from North America. Aged air masses, in combination with sporadic inputs from the upper troposphere, are observed in spring, summer and autumn. In summer time high O3 values seem to be the result of stratosphere-to-troposphere (STT exchange processes in regions neighbouring the Canary Islands. Since 1995–1996, the North Atlantic Oscillation has changed from a predominantly high positive phase to alternating between negative

  20. A detailed gravimetric geoid from North America to Eurasia

    Science.gov (United States)

    Vincent, S. F.; Strange, W. E.; Marsh, J. G.

    1972-01-01

    A detailed gravimetric geoid of the United States, North Atlantic, and Eurasia, which was computed from a combination of satellite derived and surface gravity data, is presented. The precision of this detailed geoid is + or - 2 to + or - 3 m in the continents but may be in the range of 5 to 7 m in those areas where data is sparse. Comparisons of the detailed gravimetric geoid with results of Rapp, Fischer, and Rice for the United States, Bomford in Europe, and Heiskanen and Fischer in India are presented. Comparisons are also presented with geoid heights from satellite solutions for geocentric station coordinates in North America, the Caribbean, and Europe.

  1. First report of Pineus strobi (Hartig, 1839) (Hemiptera: Adelgidae) in western North America

    Science.gov (United States)

    Molly Darr; Scott Salom; Rachel K. Brooks; Robert G. Foottit; Gary L. Miller; Nathan P. Havill

    2018-01-01

    The pine bark adelgid, Pineus strobi (Hartig, 1839) (Hempitera: Adelgidae), is native to eastern North America and is found throughout the natural range of its main host species, eastern white pine, Pinus strobus L. (Pinaceae), which stretches from the Atlantic coast, west to Ontario and Minnesota (Drooz 1985). For the first...

  2. Seasonal predictability of the North Atlantic Oscillation

    Science.gov (United States)

    Vellinga, Michael; Scaife, Adam

    2015-04-01

    Until recently, long-range forecast systems showed only modest levels of skill in predicting surface winter climate around the Atlantic Basin and associated fluctuations in the North Atlantic Oscillation at seasonal lead times. Here we use a new forecast system to assess seasonal predictability of winter North Atlantic climate. We demonstrate that key aspects of European and North American winter climate and the surface North Atlantic Oscillation are highly predictable months ahead. We demonstrate high levels of prediction skill in retrospective forecasts of the surface North Atlantic Oscillation, winter storminess, near-surface temperature, and wind speed, all of which have high value for planning and adaptation to extreme winter conditions. Analysis of forecast ensembles suggests that while useful levels of seasonal forecast skill have now been achieved, key sources of predictability are still only partially represented and there is further untapped predictability. This work is distributed under the Creative Commons Attribution 3.0 Unported License together with an author copyright. This license does not conflict with the regulations of the Crown Copyright.

  3. The North Atlantic Oscillation: variability and interactions with the North Atlantic ocean and Artic sea ice

    Energy Technology Data Exchange (ETDEWEB)

    Jung, T

    2000-07-01

    The North Atlantic oscillation (NAO) represents the dominant mode of atmospheric variability in the North Atlantic region and describes the strengthening and weakening of the midlatitude westerlies. In this study, variability of the NAO during wintertime and its relationship to the North Atlantic ocean and Arctic sea ice is investigated. For this purpose, observational data are analyzed along with integrations of models for the Atlantic ocean, Arctic sea ice, and the coupled global climate system. From a statistical point of view, the observed NAO index shows unusually high variance on interdecadal time scales during the 20th century. Variability on other time scales is consistent with realizations of random processes (''white noise''). Recurrence of wintertime NAO anomalies from winter-to-winter with missing signals during the inbetween nonwinter seasons is primarily associated with interdecadal variability of the NAO. This recurrence indicates that low-frequency changes of the NAO during the 20th century were in part externally forced. (orig.)

  4. The North Atlantic Oscillation: variability and interactions with the North Atlantic ocean and Artic sea ice

    Energy Technology Data Exchange (ETDEWEB)

    Jung, T.

    2000-07-01

    The North Atlantic oscillation (NAO) represents the dominant mode of atmospheric variability in the North Atlantic region and describes the strengthening and weakening of the midlatitude westerlies. In this study, variability of the NAO during wintertime and its relationship to the North Atlantic ocean and Arctic sea ice is investigated. For this purpose, observational data are analyzed along with integrations of models for the Atlantic ocean, Arctic sea ice, and the coupled global climate system. From a statistical point of view, the observed NAO index shows unusually high variance on interdecadal time scales during the 20th century. Variability on other time scales is consistent with realizations of random processes (''white noise''). Recurrence of wintertime NAO anomalies from winter-to-winter with missing signals during the inbetween nonwinter seasons is primarily associated with interdecadal variability of the NAO. This recurrence indicates that low-frequency changes of the NAO during the 20th century were in part externally forced. (orig.)

  5. The key role of topography in altering North Atlantic atmospheric circulation during the last glacial period

    Directory of Open Access Journals (Sweden)

    F. S. R. Pausata

    2011-10-01

    Full Text Available The Last Glacial Maximum (LGM; 21 000 yr before present was a period of low atmospheric greenhouse gas concentrations, when vast ice sheets covered large parts of North America and Europe. Paleoclimate reconstructions and modeling studies suggest that the atmospheric circulation was substantially altered compared to today, both in terms of its mean state and its variability. Here we present a suite of coupled model simulations designed to investigate both the separate and combined influences of the main LGM boundary condition changes (greenhouse gases, ice sheet topography and ice sheet albedo on the mean state and variability of the atmospheric circulation as represented by sea level pressure (SLP and 200-hPa zonal wind in the North Atlantic sector. We find that ice sheet topography accounts for most of the simulated changes during the LGM. Greenhouse gases and ice sheet albedo affect the SLP gradient in the North Atlantic, but the overall placement of high and low pressure centers is controlled by topography. Additional analysis shows that North Atlantic sea surface temperatures and sea ice edge position do not substantially influence the pattern of the climatological-mean SLP field, SLP variability or the position of the North Atlantic jet in the LGM.

  6. Piscine Orthoreovirus from Western North America Is Transmissible to Atlantic Salmon and Sockeye Salmon but Fails to Cause Heart and Skeletal Muscle Inflammation.

    Science.gov (United States)

    Garver, Kyle A; Johnson, Stewart C; Polinski, Mark P; Bradshaw, Julia C; Marty, Gary D; Snyman, Heindrich N; Morrison, Diane B; Richard, Jon

    2016-01-01

    Heart and skeletal muscle inflammation (HSMI) is a significant and often fatal disease of cultured Atlantic salmon in Norway. The consistent presence of Piscine orthoreovirus (PRV) in HSMI diseased fish along with the correlation of viral load and antigen with development of lesions has supported the supposition that PRV is the etiologic agent of this condition; yet the absence of an in vitro culture system to demonstrate disease causation and the widespread prevalence of this virus in the absence of disease continues to obfuscate the etiological role of PRV with regard to HSMI. In this study, we explore the infectivity and disease causing potential of PRV from western North America-a region now considered endemic for PRV but without manifestation of HSMI-in challenge experiments modeled upon previous reports associating PRV with HSMI. We identified that western North American PRV is highly infective by intraperitoneal injection in Atlantic salmon as well as through cohabitation of both Atlantic and Sockeye salmon. High prevalence of viral RNA in peripheral blood of infected fish persisted for as long as 59 weeks post-challenge. Nevertheless, no microscopic lesions, disease, or mortality could be attributed to the presence of PRV, and only a minor transcriptional induction of the antiviral Mx gene occurred in blood and kidney samples during log-linear replication of viral RNA. Comparative analysis of the S1 segment of PRV identified high similarity between this North American sequence and previous sequences associated with HSMI, suggesting that factors such as viral co-infection, alternate PRV strains, host condition, or specific environmental circumstances may be required to cause this disease.

  7. Piscine Orthoreovirus from Western North America Is Transmissible to Atlantic Salmon and Sockeye Salmon but Fails to Cause Heart and Skeletal Muscle Inflammation.

    Directory of Open Access Journals (Sweden)

    Kyle A Garver

    Full Text Available Heart and skeletal muscle inflammation (HSMI is a significant and often fatal disease of cultured Atlantic salmon in Norway. The consistent presence of Piscine orthoreovirus (PRV in HSMI diseased fish along with the correlation of viral load and antigen with development of lesions has supported the supposition that PRV is the etiologic agent of this condition; yet the absence of an in vitro culture system to demonstrate disease causation and the widespread prevalence of this virus in the absence of disease continues to obfuscate the etiological role of PRV with regard to HSMI. In this study, we explore the infectivity and disease causing potential of PRV from western North America-a region now considered endemic for PRV but without manifestation of HSMI-in challenge experiments modeled upon previous reports associating PRV with HSMI. We identified that western North American PRV is highly infective by intraperitoneal injection in Atlantic salmon as well as through cohabitation of both Atlantic and Sockeye salmon. High prevalence of viral RNA in peripheral blood of infected fish persisted for as long as 59 weeks post-challenge. Nevertheless, no microscopic lesions, disease, or mortality could be attributed to the presence of PRV, and only a minor transcriptional induction of the antiviral Mx gene occurred in blood and kidney samples during log-linear replication of viral RNA. Comparative analysis of the S1 segment of PRV identified high similarity between this North American sequence and previous sequences associated with HSMI, suggesting that factors such as viral co-infection, alternate PRV strains, host condition, or specific environmental circumstances may be required to cause this disease.

  8. Atmospheric and precipitation chemistry over the North Atlantic Ocean: Shipboard results, April-May 1984

    Science.gov (United States)

    Church, T. M.; Tramontano, J. M.; Whelpdale, D. M.; Andreae, M. O.; Galloway, J. N.; Keene, W. C.; Knap, A. H.; Tokos, J.

    1991-10-01

    During a North Atlantic cruise from Dakar, Senegal, to Woods Hole, Massachusetts (April 14-May 11, 1984), crossing the area of 14°-48°N; 17°-70°W, we collected atmospheric aerosols (C, N, S species), gases (SO4, HNO3, dimethyl sulfide (DMS), synthetic organic chemicals), and precipitation (major inorganic/organic ions, trace metals). Air masses that had not contacted land for over 5 days had a composition close to that from the remote marine atmosphere. Oxidation of biogenic DMS to SO4= aerosol accounted for most nss-SO4= in these air masses. Air masses that had transected densely populated North America (in the westerlies) or the Mediterranean/North Africa ( in the easterlies) within 2-5 days of being sampled over the North Atlantic were enriched in acid precursor compounds and synthetic hydrocarbons relative to air that had spent longer over the North Atlantic. Strong acids and trace metals were also elevated in precipitation. Air masses that had transected regions of strong emissions within the preceding 2 days had concentrations of atmospheric pollutants approaching those typically found in continental air masses. More frequent storm tracks between the Icelandic low and the Bermuda high favored transport of North American emissions northeasterly, toward Europe. Trajectory analyses suggested that air masses sampled off the northwest African coast had passed over the Mediterranean. Composition of the aerosol and precipitation of these air masses was also indicative of continental emissions, including biomass and petroleum burning. Transport and deposition of continental emissions to the North Atlantic were significantly influencing surface atmospheric and oceanic chemistry of this region.

  9. The relative importance of ENSO and tropical Atlantic sea surface temperature anomalies for seasonal precipitation over South America: a numerical study

    Science.gov (United States)

    Pezzi, L. P.; Cavalcanti, I. F. A.

    The role of tropical Atlantic sea surface temperature (SST) anomalies during ENSO episodes over northeast Brazil (Nordeste) is investigated using the CPTEC/COLA Atmospheric General Circulation Model (AGCM). Four sets of integrations are performed using SST in El Niño and La Niña (ENSO) episodes, changing the SST of the Atlantic Ocean. A positive dipole (SST higher than normal in the tropical North Atlantic and below normal in the tropical South Atlantic) and a negative dipole (opposite conditions), are set as the boundary conditions of SST in the Atlantic Ocean. The four experiments are performed using El Niño or La Niña SST in all oceans, except in the tropical Atlantic where the two phases of the SST dipole are applied. Five initial conditions were integrated in each case in order to obtain four ensemble results. The positive SST dipole over the tropical Atlantic Ocean and El Niño conditions over the Pacific Ocean resulted in dry conditions over the Nordeste. When the negative dipole and El Niño conditions over the Pacific Ocean were applied, the results showed precipitation above normal over the north of Nordeste. When La Niña conditions over Pacific Ocean were tested together with a negative dipole, positive precipitation anomalies occurred over the whole Nordeste. Using the positive dipole over the tropical Atlantic, the precipitation over Nordeste was below average. During La Niña episodes, the Atlantic Ocean conditions have a larger effect on the precipitation of Nordeste than the Pacific Ocean. In El Niño conditions, only the north region of Nordeste is affected by the Atlantic SST. Other tropical areas of South America show a change only in the intensity of anomalies. Central and southeast regions of South America are affected by the Atlantic conditions only during La Niña conditions, whereas during El Niño these regions are influenced only by conditions in the Pacific Ocean.

  10. The influence of cut off lows on sulfate burdens over the North Atlantic during April, 1987

    Energy Technology Data Exchange (ETDEWEB)

    Benkovitz, C.M.; Miller, M.A.; Schwartz, S.E.; Kwon, O.U.

    2001-01-14

    The authors have presented examples from a modeling study of the development of sulfur burdens over North America, the North Atlantic Ocean and Europe during April, 1987 using observation-derived meteorological data to represent the actual conditions for this period, focusing on the influence of cut-off lows on SO{sub 2} and sulfate column burdens over the North Atlantic Ocean. The analysis demonstrates that these systems can serve either as sources or sinks of sulfate, and that the major factor governing their resulting effect is the position during its formative stages relative to (a) sources of moisture, and (b) sulfur emissions, which regulates the availability of sulfur, cloud liquid water for sulfur oxidation, and the amount of precipitation for sulfate removal produced in the later stages of the life cycle.

  11. The East Atlantic - West Russia Teleconnection in the North Atlantic: Climate Impact and Relation to Rossby Wave Propagation

    Science.gov (United States)

    Lim, Young-Kwon

    2014-01-01

    Large-scale winter teleconnection of the East Atlantic - West Russia (EA-WR) over the Atlantic and surrounding regions is examined in order to quantify its impacts on temperature and precipitation and identify the physical mechanisms responsible for its existence. A rotated empirical orthogonal function (REOF) analysis of the upper-tropospheric monthly height field captures successfully the EA-WR pattern and its interannual variation, with the North Atlantic Oscillation as the first mode. EA-WRs climate impact extends from eastern North America to Eurasia. The positive (negative) EA-WR produces positive (negative) temperature anomalies over the eastern US, western Europe and Russia east of Caspian Sea, with negative (positive) anomalies over eastern Canada, eastern Europe including Ural Mountains and the Middle East. These anomalies are largely explained by lower-tropospheric temperature advections. Positive (negative) precipitation anomalies are found over the mid-latitude Atlantic and central Russia around 60E, where lower-level cyclonic (anticyclonic) circulation anomaly is dominant. The eastern Canada and the western Europe are characterized by negative (positive) precipitation anomalies.The EA-WR is found to be closely associated with Rossby wave propagation. Wave activity fluxes show that it is strongly tied to large-scale stationary waves. Furthermore, a stationary wave model (SWM) forced with vorticity transients in the mid-latitude Atlantic (approximately 40N) or diabatic heat source over the subtropical Atlantic near the Caribbean Sea produces well-organized EA-WR-like wave patterns, respectively. Sensitivity tests with the SWM indicate improvement in the simulation of the EA-WR when the mean state is modified to have a positive NAO component that enhances upper-level westerlies between 40-60N.

  12. The Okhotsk Plate and the Eurasia-North America plate boundary zone.

    Science.gov (United States)

    Hindle, David; Mackey, Kevin

    2014-05-01

    The Eurasia-North America plate boundary zone transitions from spreading at rates of ~ 25mm/yr in the North Atlantic, to compression at rates of ~ 5mm/yr in the region of the Okhotsk plate. Because the pole of rotation between Eurasia and North America lies more or less on their mutual boundary, there is a linear change in rate along the boundary, and regions near the euler pole are subject to extremely low deformation rates. The Okhotsk - Eurasia - North America triple junction lies slightly south of the rotation pole, placing the Okhotsk plate entirely in a weakly contractional setting. Regions near the triple junction absorb 1mm/yr contraction. Further south, towards the shoreline of the Okhotsk sea, up to 5 mm/yr contraction may be absorbed within the plate. How shortening is accommodated across the boundary remains an open question. One possibility is wholesale extrusion of the entire Okhotsk plate (or possibly its northwestern corner) along two plate boundary strike slip faults (Eurasia-Okhostk and North America Okhotsk). The problem with this model is that the seismic record does not presently clearly support it, with the largest events distributed both within the plate interior and on its boundaries. This may suggest that instead, the Okhotsk plate, and particularly its north-western end, consists of a series of smaller blocks which shuffle against each other, partially accommodating extrusion, but also permitting some internal deformation and change of shape of the Okhotsk plate itself. We present analyses of the very sparse seismic record from the region, as well as geometric-kinematic, tectonic models of the possible deformation of northwest Okhotsk to try to better understand the different probabilities of how this slowly deforming plate boundary zone is behaving.

  13. Tomotectonic constraints on deformation of Cordilleran North America since Late Jurassic

    Science.gov (United States)

    Mihalynuk, M. G.; Sigloch, K.

    2017-12-01

    Seismic tomography reveals detailed mantle structure beneath North America, largely thanks to USArray. TWO massive composite slabs are recognized down to 2000 km depth and their topologies are combined with quantitative plate reconstructions back to the breakup of Pangea using Atlantic and Pacific magnetic isochrons. This tomotectonic analysis reveals evolving arc/trench-plate geometries of a vast archipelago/microcontinent and ocean plateau that were overridden by North America, and an explanation for Cordilleran deformation episodes. As Pangea fragmented, subduction reconfigured from EAST-directed beneath the continent (during final growth of the Intermontane Superterrane, IMS, or "AltaBC"), to WEST-directed beneath an intraoceanic, massive arc chevron (MAC). MAC trenches were stationary within a mantle reference frame, as indicated by near-vertical slab walls 4-7x as thick as mature ocean lithosphere, and its trenches were >10,000 km long. East-pointing MAC apex was located 2000-4000 km off Pangea's west coast where MAC arc was built atop the Insular superterrane (INS, or "BajaBC"), a microcontinent extending >2600 km southwards from the apex. Ocean lithosphere between the MAC apex and west-drifting North America was consumed by 155 Ma. INS, comparable in length to the Indian subcontinent, initially collided with the leading edge of North America/IMS and generated "Nevadan" deformation. Diachronous Sevier deformation followed as MAC was driven farther into the continental margin and raked southward (sinistral offsets w.r.t. North America). By 130 Ma, with large segments accreted and MAC geometry breaking down, subduction was forced to jump outboard (westward) of MAC. The Franciscan accretionary complex marks a return to eastward/Andean-style subduction (of the Farallon plate). A remarkably complete analogue for collision at 130 Ma is found in modern Australia's override of arcs to its north. Rapid northward transport of BajaBC w.r.t. North America 90-50 Ma is

  14. Variability of North Sea pH and CO2 in response to North Atlantic Oscillation forcing

    DEFF Research Database (Denmark)

    Salt, Lesley A.; Thomas, Helmuth; Prowe, Friederike

    2013-01-01

    [1] High biological activity causes a distinct seasonality of surface water pH in the North Sea, which is a strong sink for atmospheric CO2 via an effective shelf pump. The intimate connection between the North Sea and the North Atlantic Ocean suggests that the variability of the CO2 system...... of the North Atlantic Ocean may, in part, be responsible for the observed variability of pH and CO2 in the North Sea. In this work, we demonstrate the role of the North Atlantic Oscillation (NAO), the dominant climate mode for the North Atlantic, in governing this variability. Based on three extensive...... observational records covering the relevant levels of the NAO index, we provide evidence that the North Sea pH and CO2 system strongly responds to external and internal expressions of the NAO. Under positive NAO, the higher rates of inflow of water from the North Atlantic Ocean and the Baltic outflow lead...

  15. 76 FR 14101 - Bruss North America; Russell Springs, KY; Bruss North America; Orion, MI; Amended Revised...

    Science.gov (United States)

    2011-03-15

    ... America; Russell Springs, KY; Bruss North America; Orion, MI; Amended Revised Determination on... relevant time period at the Orion, Michigan location of Bruss North America, Inc. The Orion, Michigan..., Kentucky facility also led to worker separations at the Orion, Michigan location during the relevant time...

  16. Seasonal Climate Associated with Major Shipping Routes in the North Pacific and North Atlantic

    Directory of Open Access Journals (Sweden)

    Jau-Ming Chen

    2014-01-01

    Full Text Available The major shipping routes in the North Pacific (NP and North Atlantic (NA are analyzed via ship-reported records compiled by the International Comprehensive Ocean-Atmosphere Data Set (ICOADS. The shipping route seasonal characteristics and associated climatic features are also examined. In the NP, the dominant cross-basin route takes a great-circle path between East Asia and North America along 54°N north of the Aleutian Islands throughout the year. This route penetrates the Aleutian low center where ocean waves and winds are relatively weaker than those in the low¡¦s southern section south of 50°N. Moreover, the Earth¡¦s spherical shape makes a higher-latitude route shorter in navigational distance across the NP than a lower-latitude route. Two additional mid-latitude routes through the 40° - 50°N region appear in summer when the Aleutian low vanishes. In the NA, the major shipping routes form an X-shaped pattern in the oceans south of 40°N to connect North America/the Panama Canal and the Mediterranean Sea/the British Isles and Europe. These major shipping routes are far from the influence of the Icelandic low and thus are used throughout the year due to the stability in marine conditions and their general efficiency. A third and more zonal route appears to the north of the X-shaped routes in the 40° - 50°N region. Weak influence from the Icelandic low on marine conditions during summer and spring means that more ships take this route in summer and spring than in winter and fall.

  17. Impacts of SST anomalies on the North Atlantic atmospheric circulation: a case study for the northern winter 1995/1996

    Energy Technology Data Exchange (ETDEWEB)

    Losada, T.; Rodriguez-Fonseca, B. [Universidad Complutense de Madrid, Departmento de Geofisica y Meteorologia, Madrid (Spain); Mechoso, C.R.; Ma, H.Y. [University of California Los Angeles, Department of Atmospheric and Oceanic Sciences, Los Angeles, CA (United States)

    2007-12-15

    The present paper selects the northern winter of December 1995-February 1996 for a case study on the impact of sea surface temperature (SST) anomalies on the atmospheric circulation over the North Atlantic and Western Europe. In the Atlantic, the selected winter was characterized by positive SST anomalies over the northern subtropics and east of Newfoundland, and negative anomalies along the US coast. A weak La Nina event developed in the Pacific. The North Atlantic Oscillation (NAO) index was low, precipitation over the Iberian Peninsula and northern Africa was anomalously high, and precipitation over northern Europe was anomalously low. The method of study consists of assessing the sensitivity of ensemble simulations by the UCLA atmospheric general circulation model (UCLA AGCM) to SST anomalies from the observation, which are prescribed either in the World Oceans, the Atlantic Ocean only, or the subtropical North Atlantic only. The results obtained are compared with a control run that uses global, time-varying climatological SST. The ensemble simulations with global and Atlantic-only SST anomalies both produce results that resemble the observations over the North Atlantic and Western Europe. It is suggested that the anomalous behavior of the atmosphere in the selected winter over those regions, therefore, was primarily determined by conditions within the Atlantic basin. The simulated fields in the tropical North Atlantic show anomalous upward motion and lower (upper) level convergence (divergence) in the atmosphere overlying the positive SST anomalies. Consistently, the subtropical jet intensifies and its core moves equatorward, and precipitation increases over northern Africa and southern Europe. The results also suggest that the SST anomalies in the tropical North Atlantic only do not suffice to produce the atmospheric anomalies observed in the basin during the selected winter. The extratropical SST anomalies would provide a key contribution through increased

  18. The subpolar North Atlantic - Response to North Atlantic oscillation like forcing and Influence on the Atlantic meridional overturning circulation

    Science.gov (United States)

    Lohmann, Katja; Drange, Helge; Jungclaus, Johann

    2010-05-01

    The extent and strength of the North Atlantic subpolar gyre (SPG) changed rapidly in the mid-1990s, going from large and strong in 1995 to substantially weakened in the following years. The abrupt change in the intensity of the SPG is commonly linked to the reversal of the North Atlantic Oscillation (NAO) index, changing from strong positive to negative values, in the winter 1995/96. In this study we investigate the impact of the initial SPG state on its subsequent behavior by means of an ocean general circulation model driven by NCEP-NCAR reanalysis fields. Our sensitivity integrations suggest that the weakening of the SPG cannot be explained by the change in the atmospheric forcing alone. Rather, for the time period around 1995, the SPG was about to weaken, irrespective of the actual atmospheric forcing, due to the ocean state governed by the persistently strong positive NAO during the preceding seven years (1989 to 1995). Our analysis indicates that it was this preconditioning of the ocean, in combination with the sudden drop in the NAO in 1995/96, that lead to the strong and rapid weakening of the SPG in the second half of the 1990s. In the second part, the sensitivity of the low-frequency variability of the Atlantic meridional overturning circulation to changes in the subpolar North Atlantic is investigated using a 2000 year long control integration as well as sensitivity experiments with the MPI-M Earth System Model. Two 1000 year long sensitivity experiments will be performed, in which the low-frequency variability in the overflow transports from the Nordic Seas and in the subpolar deep water formation rates is suppressed respectively. This is achieved by nudging temperature and salinity in the GIN Sea or in the subpolar North Atlantic (up to about 1500m depth) towards a monthly climatology obtained from the last 1000 years of the control integration.

  19. The Role of Convection in Redistributing Formaldehyde to the Upper Troposphere Over North America and the North Atlantic during the Summer 2004 INTEX Campaign

    Science.gov (United States)

    Fried, Alan; Olson, Jennifer R.; Walega, Jim; Crawford, Jim H.; Chen, Gao; Weibring, Petter; Richter, Dirk; Roller, Chad; Tittel, Frank; Porter, Michael; hide

    2007-01-01

    Measurements of CH2O from a tunable diode laser absorption spectrometer (TDLAS) were acquired onboard the NASA DC-8 during the summer 2004 INTEX-NA (Intercontinental Chemical Transport Experiment - North America) campaign to test our understanding of convection and production mechanisms in the upper troposphere (UT, 6-12-km) over continental North America and the North Atlantic Ocean. Point-by-point comparisons with box model calculations, when MHP (CH3OOH) measurements were available for model constraint, resulted in a median CH2O measurement/model ratio of 0.91 in the UT. Multiple tracers were used to arrive at a set of UT CH2O background and perturbed air mass periods, and 46% of the TDLAS measurements fell within the latter category. At least 66% to 73% of these elevated UT observations were caused by enhanced production from CH2O precursors rather than direct transport of CH2O from the boundary layer. This distinction is important, since the effects from the former can last for over a week or more compared to one day or less in the case of convective transport of CH2O itself. In general, production of CH2O from CH4 was found to be the dominant source term, even in perturbed air masses. This was followed by production from MHP, methanol, PAN type compounds, and ketones, in descending order of their contribution. In the presence of elevated NO from lightning and potentially from the stratosphere, there was a definite trend in the CH2O discrepancy, which for the highest NO mixing ratios produced a median CH2O measurement/model ratio of 3.9 in the 10-12-km range. Discrepancies in CH2O and HO2 in the UT with NO were highly correlated and this provided further information as to the possible mechanism(s) responsible. These discrepancies with NO are consistent with additional production sources of both gases involving CH3O2 + NO reactions, most likely caused by unmeasured hydrocarbons.

  20. Trade in the Atlantic Basin, 2000-2012: a panoramic view

    Directory of Open Access Journals (Sweden)

    Lorena Ruano

    2013-09-01

    Full Text Available This article offers a descriptive analysis of the goods trade in the Atlantic, and provides the following data: the largest trade volume can be found in the North Atlantic and the Americas, albeit with slower growth; Africa and South America trade mainly with the North, but with a tendency towards diversification; Europe depends less on Atlantic trade than other regions, South America being the most dependent of these; Africa mainly trades with extra-regional partners; the Atlantic’s role in world trade is diminishing owing to the rise of Asia (China; exports can be divided into those from the North (products with greater added value and the South (raw materials; imports are dominated by automobiles and oil; the main challenge is the economic crisis in Europe; with the Doha round havingstalled, the Atlantic free trade agreements under negotiation (Canada-EU; TTIP are gaining importance, with the aim of boosting the flow of goods, which represents one of the largest in the world.

  1. Modes of winter precipitation variability in the North Atlantic

    Energy Technology Data Exchange (ETDEWEB)

    Zorita, E. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Hydrophysik; Saenz, J.; Fernandez, J.; Zubillaga, J. [Bilbao Univ. (Spain)

    2001-07-01

    The modes of variability of winter precipitation in the North Atlantic sector are identified by Empirical Orthogonal Functions Analysis in the NCEP/NCAR global reanalysis data sets. These modes are also present in a gridded precipitation data set over the Western Europe. The large-scale fields of atmospheric seasonal mean circulation, baroclinic activity, evaporation and humidity transport that are connected to the rainfall modes have been also analyzed in order to investigate the physical mechanisms that are causally linked to the rainfall modes. The results indicate that the leading rainfall mode is associated to the North Atlantic oscillation and represents a meridional redistribution of precipitation in the North Atlantic through displacements of the storm tracks. The second mode is related to evaporation anomalies in the Eastern Atlantic that precipitate almost entirely in the Western Atlantic. The third mode seems to be associated to meridional transport of water vapor from the Tropical Atlantic. (orig.)

  2. Sea level anomaly in the North Atlantic and seas around Europe: Long-term variability and response to North Atlantic teleconnection patterns.

    Science.gov (United States)

    Iglesias, Isabel; Lorenzo, M Nieves; Lázaro, Clara; Fernandes, M Joana; Bastos, Luísa

    2017-12-31

    Sea level anomaly (SLA), provided globally by satellite altimetry, is considered a valuable proxy for detecting long-term changes of the global ocean, as well as short-term and annual variations. In this manuscript, monthly sea level anomaly grids for the period 1993-2013 are used to characterise the North Atlantic Ocean variability at inter-annual timescales and its response to the North Atlantic main patterns of atmospheric circulation variability (North Atlantic Oscillation, Eastern Atlantic, Eastern Atlantic/Western Russia, Scandinavian and Polar/Eurasia) and main driven factors as sea level pressure, sea surface temperature and wind fields. SLA variability and long-term trends are analysed for the North Atlantic Ocean and several sub-regions (North, Baltic and Mediterranean and Black seas, Bay of Biscay extended to the west coast of the Iberian Peninsula, and the northern North Atlantic Ocean), depicting the SLA fluctuations at basin and sub-basin scales, aiming at representing the regions of maximum sea level variability. A significant correlation between SLA and the different phases of the teleconnection patterns due to the generated winds, sea level pressure and sea surface temperature anomalies, with a strong variability on temporal and spatial scales, has been identified. Long-term analysis reveals the existence of non-stationary inter-annual SLA fluctuations in terms of the temporal scale. Spectral density analysis has shown the existence of long-period signals in the SLA inter-annual component, with periods of ~10, 5, 4 and 2years, depending on the analysed sub-region. Also, a non-uniform increase in sea level since 1993 is identified for all sub-regions, with trend values between 2.05mm/year, for the Bay of Biscay region, and 3.98mm/year for the Baltic Sea (no GIA correction considered). The obtained results demonstrated a strong link between the atmospheric patterns and SLA, as well as strong long-period fluctuations of this variable in spatial and

  3. Environmental Composites for Bomb Cyclones of the Western North Atlantic in Reanalysis, 1948-2016.

    Science.gov (United States)

    Adams, R.; Sheridan, S. C.

    2017-12-01

    "Bomb" cyclones represent a small subset of mid-latitude cyclones characterized by rapid intensification and frequently are associated with extreme weather conditions along the eastern coast of North America. Like other extreme phenomena, bomb cyclone predictions are prone to error leading to inadequate or untimely hazard warnings. The rare nature of bomb cyclones and the uniqueness of their evolutions has made it difficult for researchers to make meaningful generalizations on bomb cyclone events. This paper describes bomb cyclone climatology for the western North Atlantic, using data from the NCEP-NCAR Reanalysis for 1948-2016, and uses a synoptic climatological analysis to relate these bombs to their associated atmospheric environments. A self-organizing map (SOM) of 300-hPa geopotential height tendency is created to partition the regional atmospheric environment. Thermodynamic fields are contrasted by each 300-hPa geopotential height tendency pattern for both bomb and non-bomb events in composite difference maps. The SOM patterns most significantly associated with western North Atlantic bomb cyclogenesis are characterized by both strongly and weakly negative height tendencies along the eastern United States. In both cases, these patterns exhibit strong meridional flow, a distinction marked by the weakening and breaking down of the polar vortex in the boreal Winter. The composite maps for each pattern show the mean differences in low-mid level ascent and near surface thermodynamics for bomb environments contrasted with non-bomb environments, resulting in diverse spatiotemporal distributions of bombs in the western North Atlantic.

  4. Drivers and potential predictability of summer time North Atlantic polar front jet variability

    Science.gov (United States)

    Hall, Richard J.; Jones, Julie M.; Hanna, Edward; Scaife, Adam A.; Erdélyi, Róbert

    2017-06-01

    The variability of the North Atlantic polar front jet stream is crucial in determining summer weather around the North Atlantic basin. Recent extreme summers in western Europe and North America have highlighted the need for greater understanding of this variability, in order to aid seasonal forecasting and mitigate societal, environmental and economic impacts. Here we find that simple linear regression and composite models based on a few predictable factors are able to explain up to 35 % of summertime jet stream speed and latitude variability from 1955 onwards. Sea surface temperature forcings impact predominantly on jet speed, whereas solar and cryospheric forcings appear to influence jet latitude. The cryospheric associations come from the previous autumn, suggesting the survival of an ice-induced signal through the winter season, whereas solar influences lead jet variability by a few years. Regression models covering the earlier part of the twentieth century are much less effective, presumably due to decreased availability of data, and increased uncertainty in observational reanalyses. Wavelet coherence analysis identifies that associations fluctuate over the study period but it is not clear whether this is just internal variability or genuine non-stationarity. Finally we identify areas for future research.

  5. Oceanographic profile of temperature, salinity, oxygen and other measurements collected using bottle in the North Atlantic from 1960 - 1972 (NODC Accession 0001079)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data were collected by AtlantNIRO of Kalinigrad, USSR during fisheries cruises along the northeast coast of North America from 06 April 1960 to 20 July 1972....

  6. 78 FR 2287 - Daimler Buses North America, Inc., a Subsidiary of Daimler North America Corp, Including On-Site...

    Science.gov (United States)

    2013-01-10

    ... subsidiary of Daimler North America Corp., including on-site leased workers from Noramtec, First Choice... America, Inc., a Subsidiary of Daimler North America Corp, Including On-Site Leased Workers From Noramtec, First Choice Staffing, Staff Works, and Mr. Santo Lamarco From Wurth Revcar Fasteners, Inc., Oriskany...

  7. Asymmetric response of tropical cyclone activity to global warming over the North Atlantic and western North Pacific from CMIP5 model projections.

    Science.gov (United States)

    Park, Doo-Sun R; Ho, Chang-Hoi; Chan, Johnny C L; Ha, Kyung-Ja; Kim, Hyeong-Seog; Kim, Jinwon; Kim, Joo-Hong

    2017-01-30

    Recent improvements in the theoretical understanding of the relationship between tropical cyclones (TCs) and their large-scale environments have resulted in significant improvements in the skill for forecasting TC activity at daily and seasonal time-scales. However, future changes in TC activity under a warmer climate remain uncertain, particularly in terms of TC genesis locations and subsequent pathways. Applying a track-pattern-based statistical model to 22 Coupled Model Intercomparison Project Phase 5 (CMIP5) model runs for the historical period and the future period corresponding to the Representative Concentration Pathway 8.5 emissions scenarios, this study shows that in future climate conditions, TC passage frequency will decrease over the North Atlantic, particularly in the Gulf of Mexico, but will increase over the western North Pacific, especially that hits Korea and Japan. Unlike previous studies based on fine-resolution models, an ensemble mean of CMIP5 models projects an increase in TC activity in the western North Pacific, which is owing to enhanced subtropical deep convection and favorable dynamic conditions therein in conjunction with the expansion of the tropics and vice versa for the North Atlantic. Our results suggest that North America will experience less TC landfalls, while northeast Asia will experience more TCs than in the present-day climate.

  8. Anthropogenic and climatic influences on carbon fluxes from eastern North America to the Atlantic Ocean: A process-based modeling study

    Science.gov (United States)

    Tian, Hanqin; Yang, Qichun; Najjar, Raymond G.; Ren, Wei; Friedrichs, Marjorie A. M.; Hopkinson, Charles S.; Pan, Shufen

    2015-04-01

    The magnitude, spatiotemporal patterns, and controls of carbon flux from land to the ocean remain uncertain. Here we applied a process-based land model with explicit representation of carbon processes in streams and rivers to examine how changes in climate, land conversion, management practices, atmospheric CO2, and nitrogen deposition affected carbon fluxes from eastern North America to the Atlantic Ocean, specifically the Gulf of Maine (GOM), Middle Atlantic Bight (MAB), and South Atlantic Bight (SAB). Our simulation results indicate that the mean annual fluxes (±1 standard deviation) of dissolved organic carbon (DOC), particulate organic carbon (POC), and dissolved inorganic carbon (DIC) in the past three decades (1980-2008) were 2.37 ± 0.60, 1.06 ± 0.20, and 3.57 ± 0.72 Tg C yr-1, respectively. Carbon export demonstrated substantial spatial and temporal variability. For the region as a whole, the model simulates a significant decrease in riverine DIC fluxes from 1901 to 2008, whereas there were no significant trends in DOC or POC fluxes. In the SAB, however, there were significant declines in the fluxes of all three forms of carbon, and in the MAB subregion, DIC and POC fluxes declined significantly. The only significant trend in the GOM subregion was an increase in DIC flux. Climate variability was the primary cause of interannual variability in carbon export. Land conversion from cropland to forest was the primary factor contributing to decreases in all forms of C export, while nitrogen deposition and fertilizer use, as well as atmospheric CO2 increases, tended to increase DOC, POC, and DIC fluxes.

  9. Species dominance and equitability: patterns in Cenozoic foraminifera of eastern North America

    Science.gov (United States)

    Gibson, T.G.; Hill, E.E.

    1992-01-01

    Species dominance in benthonic foraminifera, represented by percent of the assemblage composed of the single most abundant species, shows little change in observed range of values from shallow into deep-marine waters in 1005 samples from the Gulf of Mexico, Atlantic, and Arctic margins of North America. This finding contrasts with the model that species dominance is highest in shallow-marine environments and decreases offshore into deeper marine waters. Equitability, the relation of all species abundances within an assemblage, also shows little change between the values found in shallow-marine assemblages and those found in assemblages from deeper water environments. Equitability and dominance values found in 421 assemblages from Palaeocene, Eocene, Miocene, and Pleistocene strata of the Atlantic and E Gulf of Mexico coastal plains are similar to the modern values. -from Authors

  10. Marine biodiversity in the Atlantic and Pacific coasts of South America: knowledge and gaps.

    Science.gov (United States)

    Miloslavich, Patricia; Klein, Eduardo; Díaz, Juan M; Hernández, Cristián E; Bigatti, Gregorio; Campos, Lucia; Artigas, Felipe; Castillo, Julio; Penchaszadeh, Pablo E; Neill, Paula E; Carranza, Alvar; Retana, María V; Díaz de Astarloa, Juan M; Lewis, Mirtha; Yorio, Pablo; Piriz, María L; Rodríguez, Diego; Yoneshigue-Valentin, Yocie; Gamboa, Luiz; Martín, Alberto

    2011-01-31

    The marine areas of South America (SA) include almost 30,000 km of coastline and encompass three different oceanic domains--the Caribbean, the Pacific, and the Atlantic--ranging in latitude from 12∘N to 55∘S. The 10 countries that border these coasts have different research capabilities and taxonomic traditions that affect taxonomic knowledge. This paper analyzes the status of knowledge of marine biodiversity in five subregions along the Atlantic and Pacific coasts of South America (SA): the Tropical East Pacific, the Humboldt Current,the Patagonian Shelf, the Brazilian Shelves, and the Tropical West Atlantic, and it provides a review of ecosystem threats and regional marine conservation strategies. South American marine biodiversity is least well known in the tropical subregions (with the exception of Costa Rica and Panama). Differences in total biodiversity were observed between the Atlantic and Pacific oceans at the same latitude. In the north of the continent, the Tropical East Pacific is richer in species than the Tropical West Atlantic, however, when standardized by coastal length, there is very little difference among them. In the south, the Humboldt Current system is much richer than the Patagonian Shelf. An analysis of endemism shows that 75% of the species are reported within only one of the SA regions, while about 22% of the species of SA are not reported elsewhere in the world. National and regional initiatives focusing on new exploration, especially to unknown areas and ecosystems, as well as collaboration among countries are fundamental to achieving the goal of completing inventories of species diversity and distribution.These inventories will allow accurate interpretation of the biogeography of its two oceanic coasts and latitudinal trends,and will also provide relevant information for science based policies.

  11. Parasites as biological tags of marine, freshwater and anadromous fishes in North America from the Tropics to the Arctic.

    Science.gov (United States)

    Marcogliese, David J; Jacobson, Kym C

    2015-01-01

    Parasites have been considered as natural biological tags of marine fish populations in North America for almost 75 years. In the Northwest Atlantic, the most studied species include Atlantic cod (Gadus morhua), Atlantic herring (Clupea harengus) and the redfishes (Sebastes spp.). In the North Pacific, research has centred primarily on salmonids (Oncorhynchus spp.). However, parasites have been applied as tags for numerous other pelagic and demersal species on both the Atlantic and Pacific coasts. Relatively few studies have been undertaken in the Arctic, and these were designed to discriminate anadromous and resident salmonids (Salvelinus spp.). Although rarely applied in fresh waters, parasites have been used to delineate certain fish stocks within the Great Lakes-St Lawrence River basin. Anisakid nematodes and the copepod Sphyrion lumpi frequently prove useful indicators in the Northwest Atlantic, while myxozoan parasites prove very effective on the coast and open seas of the Pacific Ocean. Relative differences in the ability of parasites to discriminate between fish stocks on the Pacific and Atlantic coasts may be due to oceanographic and bathymetric differences between regions. Molecular techniques used to differentiate populations and species of parasites show promise in future applications in the field.

  12. The role of Atlantic-Arctic exchange in North Atlantic multidecadal climate variability

    NARCIS (Netherlands)

    Frankcombe, L.M.; Dijkstra, H.A.

    2011-01-01

    It has recently been suggested that multidecadal variability in North Atlantic sea surface temperature occurs with two dominant periods. In this paper we investigate the origin of these two time scales in a 500 year control run of the GFDL CM2.1 model. We focus on the exchange between the Atlantic

  13. An anatomy of the projected North Atlantic warming hole in CMIP5 models

    Science.gov (United States)

    Menary, Matthew B.; Wood, Richard A.

    2018-04-01

    Global mean surface air temperature has increased over the past century and climate models project this trend to continue. However, the pattern of change is not homogeneous. Of particular interest is the subpolar North Atlantic, which has cooled in recent years and is projected to continue to warm less rapidly than the global mean. This is often termed the North Atlantic warming hole (WH). In climate model projections, the development of the WH is concomitant with a weakening of the Atlantic meridional overturning circulation (AMOC). Here, we further investigate the possible link between the AMOC and WH and the competing drivers of vertical mixing and surface heat fluxes. Across a large ensemble of 41 climate models we find that the spatial structure of the WH varies considerably from model to model but is generally upstream of the simulated deep water formation regions. A heat budget analysis suggests the formation of the WH is related to changes in ocean heat transport. Although the models display a plethora of AMOC mean states, they generally predict a weakening and shallowing of the AMOC also consistent with the evolving depth structure of the WH. A lagged regression analysis during the WH onset phase suggests that reductions in wintertime mixing lead a weakening of the AMOC by 5 years in turn leading initiation of the WH by 5 years. Inter-model differences in the evolution and structure of the WH are likely to lead to somewhat different projected climate impacts in nearby Europe and North America.

  14. Forest health conditions in North America

    International Nuclear Information System (INIS)

    Tkacz, Borys; Moody, Ben; Castillo, Jaime Villa; Fenn, Mark E.

    2008-01-01

    Some of the greatest forest health impacts in North America are caused by invasive forest insects and pathogens (e.g., emerald ash borer and sudden oak death in the US), by severe outbreaks of native pests (e.g., mountain pine beetle in Canada), and fires exacerbated by changing climate. Ozone and N and S pollutants continue to impact the health of forests in several regions of North America. Long-term monitoring of forest health indicators has facilitated the assessment of forest health and sustainability in North America. By linking a nationwide network of forest health plots with the more extensive forest inventory, forest health experts in the US have evaluated current trends for major forest health indicators and developed assessments of future risks. Canada and Mexico currently lack nationwide networks of forest health plots. Development and expansion of these networks is critical to effective assessment of future forest health impacts. - The forests of North America continue to face many biotic and abiotic stressors including fragmentation, fires, native and invasive pests, and air pollution

  15. Marine proxy evidence linking decadal North Pacific and Atlantic climate

    Energy Technology Data Exchange (ETDEWEB)

    Hetzinger, S. [University of Toronto Mississauga, CPS-Department, Mississauga, ON (Canada); Leibniz Institute of Marine Sciences, IFM-GEOMAR, Kiel (Germany); Halfar, J. [University of Toronto Mississauga, CPS-Department, Mississauga, ON (Canada); Mecking, J.V.; Keenlyside, N.S. [Leibniz Institute of Marine Sciences, IFM-GEOMAR, Kiel (Germany); University of Bergen, Geophysical Institute and Bjerknes Centre for Climate Research, Bergen (Norway); Kronz, A. [University of Goettingen, Geowissenschaftliches Zentrum, Goettingen (Germany); Steneck, R.S. [University of Maine, Darling Marine Center, Walpole, ME (United States); Adey, W.H. [Smithsonian Institution, Department of Botany, Washington, DC (United States); Lebednik, P.A. [ARCADIS U.S. Inc., Walnut Creek, CA (United States)

    2012-09-15

    Decadal- to multidecadal variability in the extra-tropical North Pacific is evident in 20th century instrumental records and has significant impacts on Northern Hemisphere climate and marine ecosystems. Several studies have discussed a potential linkage between North Pacific and Atlantic climate on various time scales. On decadal time scales no relationship could be confirmed, potentially due to sparse instrumental observations before 1950. Proxy data are limited and no multi-centennial high-resolution marine geochemical proxy records are available from the subarctic North Pacific. Here we present an annually-resolved record (1818-1967) of Mg/Ca variations from a North Pacific/Bering Sea coralline alga that extends our knowledge in this region beyond available data. It shows for the first time a statistically significant link between decadal fluctuations in sea-level pressure in the North Pacific and North Atlantic. The record is a lagged proxy for decadal-scale variations of the Aleutian Low. It is significantly related to regional sea surface temperature and the North Atlantic Oscillation (NAO) index in late boreal winter on these time scales. Our data show that on decadal time scales a weaker Aleutian Low precedes a negative NAO by several years. This atmospheric link can explain the coherence of decadal North Pacific and Atlantic Multidecadal Variability, as suggested by earlier studies using climate models and limited instrumental data. (orig.)

  16. Contributions of Tropical Cyclones to the North Atlantic Climatological Rainfall as Observed from Satellites

    Science.gov (United States)

    Rodgers, Edward B.; Adler, Robert F.; Pierce, Harold F.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The tropical cyclone rainfall climatology study that was performed for the North Pacific was extended to the North Atlantic. Similar to the North Pacific tropical cyclone study, mean monthly rainfall within 444 km of the center of the North Atlantic tropical cyclones (i.e., that reached storm stage and greater) was estimated from passive microwave satellite observations during, an eleven year period. These satellite-observed rainfall estimates were used to assess the impact of tropical cyclone rainfall in altering the geographical, seasonal, and inter-annual distribution of the North Atlantic total rainfall during, June-November when tropical cyclones were most abundant. The main results from this study indicate: 1) that tropical cyclones contribute, respectively, 4%, 3%, and 4% to the western, eastern, and entire North Atlantic; 2) similar to that observed in the North Pacific, the maximum in North Atlantic tropical cyclone rainfall is approximately 5 - 10 deg poleward (depending on longitude) of the maximum non-tropical cyclone rainfall; 3) tropical cyclones contribute regionally a maximum of 30% of the total rainfall 'northeast of Puerto Rico, within a region near 15 deg N 55 deg W, and off the west coast of Africa; 4) there is no lag between the months with maximum tropical cyclone rainfall and non-tropical cyclone rainfall in the western North Atlantic, while in the eastern North Atlantic, maximum tropical cyclone rainfall precedes maximum non-tropical cyclone rainfall; 5) like the North Pacific, North Atlantic tropical cyclones Of hurricane intensity generate the greatest amount of rainfall in the higher latitudes; and 6) warm ENSO events inhibit tropical cyclone rainfall.

  17. Juncus planifolius (Juncaceae) in North America

    DEFF Research Database (Denmark)

    Balslev, Henrik

    1980-01-01

    Juncus planifolius is reported for the first time from North America. Bibliographic notes on this species and its synonymy are given. Its distribution, dispersal and relationships within the genus are discussed.......Juncus planifolius is reported for the first time from North America. Bibliographic notes on this species and its synonymy are given. Its distribution, dispersal and relationships within the genus are discussed....

  18. Are North Atlantic Multidecadal SST Anomalies Westward Propagating?

    NARCIS (Netherlands)

    Feng, Qingyi; Dijkstra, Hendrik

    2014-01-01

    The westward propagation of sea surface temperature (SST) anomalies is one of the main characteristics of one of the theories of the Atlantic Multidecadal Oscillation. Here we use techniques from complex network modeling to investigate the existence of the westward propagation in the North Atlantic

  19. Influence of the North Atlantic Oscillation on European tropospheric composition: an observational and modelling study

    Science.gov (United States)

    Pope, R.; Chipperfield, M.

    2017-12-01

    The North Atlantic Oscillation (NAO) has a strong influence on winter-time North Atlantic and European circulation patterns. Under the positive phase of the NAO (NAO+), intensification of the climatological Icelandic low and Azores high pressure systems results in strong westerly flow across the Atlantic into Europe. Under the NAO negative phase (NAO-), there is a weakening of this meridional pressure gradient resulting in a southerly shift in the westerlies flow towards the sub-tropical Atlantic. Therefore, NAO+ and NAO- introduce unstable stormy and drier stable conditions into Europe, respectively. Under NAO+ conditions, the strong westerlies tend to enhance transport of European pollution (e.g. nitrogen oxides) away from anthropogenic source regions. While during NAO-, the more stable conditions lead to a build up of pollutants. However, secondary pollutants (i.e. tropospheric ozone) show the opposite signal where NAO+, while transporting primary pollutants away, introduces Atlantic ozone enriched air into Europe. Here ozone can form downwind of pollution from continental North America and be transported into Europe via the westerly flow. Under NAO-, this westerly ozone transport is reduced yielding lower European ozone concentrations also depleted further by ozone loss through the reaction with NOx, which has accumulated over the continent. Peroxyacetyl nitrate (PAN), observed in the upper troposphere - lower stratosphere (UTLS) by satellite, peaks over Iceland/Southern Greenland in NAO-, between 200-100 hPa, consistent with trapping by an anticyclone at this altitude. During NAO+, PAN is enhanced over the sub-tropical Atlantic and Arctic. Model simulations show that enhanced PAN over Iceland/Southern Greenland in NAO- is associated with vertical transport from the troposphere into the UTLS, while peak Arctic PAN in NAO+ is its accumulation given the strong northerly meridional transport in the UTLS. UTLS ozone spatial anomalies, relative to the winter

  20. A role for land surface forcing of North Atlantic climate and isotope signals during the 8.2kyr event?

    Science.gov (United States)

    Hopcroft, Peter; Valdes, Paul

    2014-05-01

    An important example of abrupt climate change occurred 8200 years ago in the North Atlantic and is generally known as the 8.2kyr event. This abrupt ~160 year cooling appears to coincide with the final drainage of the ice-dammed Lakes Agassiz and Ojibway. The resultant influx of meltwater to the North Atlantic is assumed to have perturbed the Atlantic Meridional Overturning circulation, reducing northward heat transport and causing widespread cooling. Numerous lines of evidence support this theory, with reconstructions showing changes in deep water formation, reductions in salinity and evidence of sea-level rise. Coupled general circulation model (GCM) simulations driven with realistic estimates of the meltwater flux show a regional cooling but fail to replicate the duration or the magnitude of this event in comparison with proxy archives. Meltwater injection was not the only rapid climate forcing in operation at this time. Drainage of the pro-glacial lakes would have had a profound effect on the boundary layer heat fluxes over North America, with potential teleconnections further afield. In this work we use an isotope-enabled version of the coupled GCM HadCM3 with boundary conditions appropriate for the time period of 9kyr (including ice sheets, greenhouse gases and orbital parameters). This model tracks oxygen isotopes throughout the hydrological cycle allowing more robust comparison with proxy archives. We analyse the impact of the removal of a lake area corresponding to Lakes Agassiz and Ojibway at this time and present sensitivity tests designed to analyse the contributions from lake removal, orographic change and the assumed isotopic content of the pro-glacial lakes. The results show a distinct pattern of cooling across North America (in the annual mean) with an apparent teleconnection to the Barents Sea, where there is warming associated with sea-ice reduction. The isotopic implications depend on the initial isotopic content of the pro-glacial lake. Assuming

  1. Secular Changes in the Solar Semidiurnal Tide of the Western North Atlantic Ocean

    Science.gov (United States)

    Ray, Richard D.

    2009-01-01

    An analysis of twentieth century tide gauge records reveals that the solar semidiurnal tide S, has been decreasing in amplitude along the eastern coast of North America and at the mid-ocean site Bermuda. In relative terms the observed rates are unusually large, of order 10% per century. Periods of greatest change, however, are inconsistent among the stations, and roughly half the stations show increasing amplitude since the late 1990s. Excepting the Gulf of Maine, lunar tides are either static or slightly increasing in amplitude; a few stations show decreases. Large changes in solar, but not lunar, tides suggest causes related to variable radiational forcing, but the hypothesis is at present unproven. Citation: Ray, R. D. (2009), Secular changes in the solar semidiurnal tide of the western North Atlantic Ocean

  2. Endemism in the moss flora of North America.

    Science.gov (United States)

    Carter, Benjamin E; Shaw, Blanka; Shaw, A Jonathan

    2016-04-01

    Identifying regions of high endemism is a critical step toward understanding the mechanisms underlying diversification and establishing conservation priorities. Here, we identified regions of high moss endemism across North America. We also identified lineages that contribute disproportionately to endemism and document the progress of efforts to inventory the endemic flora. To understand the documentation of endemic moss diversity in North America, we tabulated species publication dates to document the progress of species discovery across the continent. We analyzed herbarium specimen data and distribution data from the Flora of North America project to delineate major regions of moss endemism. Finally, we surveyed the literature to assess the importance of intercontinental vs. within-continent diversification for generating endemic species. Three primary regions of endemism were identified and two of these were further divided into a total of nine subregions. Overall endemic richness has two peaks, one in northern California and the Pacific Northwest, and the other in the southern Appalachians. Description of new endemic species has risen steeply over the last few decades, especially in western North America. Among the few studies documenting sister species relationships of endemics, recent diversification appears to have played a larger role in western North America, than in the east. Our understanding of bryophyte endemism continues to grow rapidly. Large continent-wide data sets confirm early views on hotspots of endemic bryophyte richness and indicate a high rate of ongoing species discovery in North America. © 2016 Botanical Society of America.

  3. Database of the Geologic Map of North America - Adapted from the Map by J.C. Reed, Jr. and others (2005)

    Science.gov (United States)

    Garrity, Christopher P.; Soller, David R.

    2009-01-01

    The Geological Society of America's (GSA) Geologic Map of North America (Reed and others, 2005; 1:5,000,000) shows the geology of a significantly large area of the Earth, centered on North and Central America and including the submarine geology of parts of the Atlantic and Pacific Oceans. This map is now converted to a Geographic Information System (GIS) database that contains all geologic and base-map information shown on the two printed map sheets and the accompanying explanation sheet. We anticipate this map database will be revised at some unspecified time in the future, likely through the actions of a steering committee managed by the Geological Society of America (GSA) and staffed by scientists from agencies including, but not limited to, those responsible for the original map compilation (U.S. Geological Survey, Geological Survey of Canada, and Woods Hole Oceanographic Institute). Regarding the use of this product, as noted by the map's compilers: 'The Geologic Map of North America is an essential educational tool for teaching the geology of North America to university students and for the continuing education of professional geologists in North America and elsewhere. In addition, simplified maps derived from the Geologic Map of North America are useful for enlightening younger students and the general public about the geology of the continent.' With publication of this database, the preparation of any type of simplified map is made significantly easier. More important perhaps, the database provides a more accessible means to explore the map information and to compare and analyze it in conjunction with other types of information (for example, land use, soils, biology) to better understand the complex interrelations among factors that affect Earth resources, hazards, ecosystems, and climate.

  4. Transport and deposition of the fire biomarker levoglucosan across the tropical North Atlantic Ocean

    Science.gov (United States)

    Schreuder, Laura T.; Hopmans, Ellen C.; Stuut, Jan-Berend W.; Sinninghe Damsté, Jaap S.; Schouten, Stefan

    2018-04-01

    burning in northwestern Africa. However, close to South America levoglucosan concentrations appear to be affected by riverine transport from the Amazon River. In surface sediments close to South America, levoglucosan concentration is higher than in the middle of the Atlantic Ocean, implying that here the influence from the South American continent is important and perennial. Our study provides evidence that degradation of levoglucosan during settling in the marine water column is not substantial, but is substantial at the sediment-water interface. Nevertheless, levoglucosan was detected in all surface sediments throughout the tropical North Atlantic, indicating its presence in the marine sedimentary record, which reveals the potential for levoglucosan as a biomass burning proxy in marine sediments.

  5. Is the Central America forearc sliver part of the North America plate?

    Science.gov (United States)

    Guzman-Speziale, M.

    2012-04-01

    The Central America Forearc sliver is located between the Central America volcanic arc and the Middle America trench. Several authors have suggested that the forearc is being displaced to the northwest with respect to the Caribbean plate; they point to right-lateral, normal-faulting earthquakes along the Central America volcanic arc as prime evidence of this displacement. Apparently, the forearc continues to the northwest into southeastern Mexico, although this portion of the forearc is not being displaced. I present evidence that suggests that the forearc indeed continues into southeastern Mexico and that it belongs to the North America plate. Physiographically, there is a continuity of the forearc into the Coastal plains of southeastern (Chiapas) Mexico, across the Motagua and Polochic faults. Offshore, cross-sections of the Middle America trench are similar along the mexican (Chiapas) segment, and the Central American segment. Furthermore, at the northwestern end of the coastal plain there are no compressive structures, which suggests that the coastal plain is not being displaced to the northwest. As a matter of fact, fault-plane solutions for shallow earthquakes show extension rather than compression. Shallow, interplate earthquakes along the trench show similar parameters along both segments. P-axes and earthquake slip vectors have consistent azimuths, which relate better with Cocos-North America convergence than with Cocos-Caribbean. Azimuth of T-axes for normal-faulting earthquakes also agree well with Cocos-North America convergence. Similarity in several parameters is thus found across both segments, the Chiapas coastal plain and the Central America forearc sliver proper. This suggests that both segments are continuous and probably one and the same, and belonging to the North America plate. Perhaps more properly, the forearc sliver extends into southeastern Mexico and is part of the zone of deformation associated to the Cocos-North America-Caribbean plates

  6. The North Atlantic Ocean Is in a State of Reduced Overturning

    Science.gov (United States)

    Smeed, D. A.; Josey, S. A.; Beaulieu, C.; Johns, W. E.; Moat, B. I.; Frajka-Williams, E.; Rayner, D.; Meinen, C. S.; Baringer, M. O.; Bryden, H. L.; McCarthy, G. D.

    2018-02-01

    The Atlantic Meridional Overturning Circulation (AMOC) is responsible for a variable and climatically important northward transport of heat. Using data from an array of instruments that span the Atlantic at 26°N, we show that the AMOC has been in a state of reduced overturning since 2008 as compared to 2004-2008. This change of AMOC state is concurrent with other changes in the North Atlantic such as a northward shift and broadening of the Gulf Stream and altered patterns of heat content and sea surface temperature. These changes resemble the response to a declining AMOC predicted by coupled climate models. Concurrent changes in air-sea fluxes close to the western boundary reveal that the changes in ocean heat transport and sea surface temperature have altered the pattern of ocean-atmosphere heat exchange over the North Atlantic. These results provide strong observational evidence that the AMOC is a major factor in decadal-scale variability of North Atlantic climate.

  7. North Atlantic observations sharpen meridional overturning projections

    Science.gov (United States)

    Olson, R.; An, S.-I.; Fan, Y.; Evans, J. P.; Caesar, L.

    2018-06-01

    Atlantic Meridional Overturning Circulation (AMOC) projections are uncertain due to both model errors, as well as internal climate variability. An AMOC slowdown projected by many climate models is likely to have considerable effects on many aspects of global and North Atlantic climate. Previous studies to make probabilistic AMOC projections have broken new ground. However, they do not drift-correct or cross-validate the projections, and do not fully account for internal variability. Furthermore, they consider a limited subset of models, and ignore the skill of models at representing the temporal North Atlantic dynamics. We improve on previous work by applying Bayesian Model Averaging to weight 13 Coupled Model Intercomparison Project phase 5 models by their skill at modeling the AMOC strength, and its temporal dynamics, as approximated by the northern North-Atlantic temperature-based AMOC Index. We make drift-corrected projections accounting for structural model errors, and for the internal variability. Cross-validation experiments give approximately correct empirical coverage probabilities, which validates our method. Our results present more evidence that AMOC likely already started slowing down. While weighting considerably moderates and sharpens our projections, our results are at low end of previously published estimates. We project mean AMOC changes between periods 1960-1999 and 2060-2099 of -4.0 Sv and -6.8 Sv for RCP4.5 and RCP8.5 emissions scenarios respectively. The corresponding average 90% credible intervals for our weighted experiments are [-7.2, -1.2] and [-10.5, -3.7] Sv respectively for the two scenarios.

  8. Tropical Dominance of N2 Fixation in the North Atlantic Ocean

    Science.gov (United States)

    Marconi, Dario; Sigman, Daniel M.; Casciotti, Karen L.; Campbell, Ethan C.; Alexandra Weigand, M.; Fawcett, Sarah E.; Knapp, Angela N.; Rafter, Patrick A.; Ward, Bess B.; Haug, Gerald H.

    2017-10-01

    To investigate the controls on N2 fixation and the role of the Atlantic in the global ocean's fixed nitrogen (N) budget, Atlantic N2 fixation is calculated by combining meridional nitrate fluxes across World Ocean Circulation Experiment sections with observed nitrate 15N/14N differences between northward and southward transported nitrate. N2 fixation inputs of 27.1 ± 4.3 Tg N/yr and 3.0 ± 0.5 Tg N/yr are estimated north of 11°S and 24°N, respectively. That is, 90% of the N2 fixation in the Atlantic north of 11°S occurs south of 24°N in a region with upwelling that imports phosphorus (P) in excess of N relative to phytoplankton requirements. This suggests that, under the modern iron-rich conditions of the equatorial and North Atlantic, N2 fixation occurs predominantly in response to P-bearing, N-poor conditions. We estimate a N2 fixation rate of 30.5 ± 4.9 Tg N/yr north of 30°S, implying only 3 Tg N/yr between 30° and 11°S, despite evidence of P-bearing, N-poor surface waters in this region as well; this is consistent with iron limitation of N2 fixation in the South Atlantic. Since the ocean flows through the Atlantic surface in Pacific basins.

  9. North Atlantic explosive cyclones and large scale atmospheric variability modes

    Science.gov (United States)

    Liberato, Margarida L. R.

    2015-04-01

    Extreme windstorms are one of the major natural catastrophes in the extratropics, one of the most costly natural hazards in Europe and are responsible for substantial economic damages and even fatalities. During the last decades Europe witnessed major damage from winter storms such as Lothar (December 1999), Kyrill (January 2007), Klaus (January 2009), Xynthia (February 2010), Gong (January 2013) and Stephanie (February 2014) which exhibited uncommon characteristics. In fact, most of these storms crossed the Atlantic in direction of Europe experiencing an explosive development at unusual lower latitudes along the edge of the dominant North Atlantic storm track and reaching Iberia with an uncommon intensity (Liberato et al., 2011; 2013; Liberato 2014). Results show that the explosive cyclogenesis process of most of these storms at such low latitudes is driven by: (i) the southerly displacement of a very strong polar jet stream; and (ii) the presence of an atmospheric river (AR), that is, by a (sub)tropical moisture export over the western and central (sub)tropical Atlantic which converges into the cyclogenesis region and then moves along with the storm towards Iberia. Previous studies have pointed to a link between the North Atlantic Oscillation (NAO) and intense European windstorms. On the other hand, the NAO exerts a decisive control on the average latitudinal location of the jet stream over the North Atlantic basin (Woollings et al. 2010). In this work the link between North Atlantic explosive cyclogenesis, atmospheric rivers and large scale atmospheric variability modes is reviewed and discussed. Liberato MLR (2014) The 19 January 2013 windstorm over the north Atlantic: Large-scale dynamics and impacts on Iberia. Weather and Climate Extremes, 5-6, 16-28. doi: 10.1016/j.wace.2014.06.002 Liberato MRL, Pinto JG, Trigo IF, Trigo RM. (2011) Klaus - an exceptional winter storm over Northern Iberia and Southern France. Weather 66:330-334. doi:10.1002/wea.755 Liberato

  10. Paleohydrology of tropical South America and paleoceanography of the tropical Atlantic as deduced from two new sediment cores on the Brazilian continental slope

    Science.gov (United States)

    Nace, T.; Baker, P. A.; Dwyer, G. S.; Silva, C. G.; Hollander, D. J.; Rigsby, C. A.; Giosan, L.; Burns, S. J.

    2011-12-01

    Paleoclimate/paleoceanographic reconstructions of the Amazon Basin, Brazilian Nordeste, and western equatorial Atlantic have been undertaken on two new sediment cores located on the Brazilian continental slope (Core CDH-5 at 1708 mbsl, 4N, 48W, 32m long, ~30 ka record; Core CDH-86 at 3708 mbsl, 0N/S, 44W, 30m long, ~100ka record). High-resolution XRF analyses of Fe, Ti, and Ca are used to define the paleohydrologic history of the adjacent continent at both sites. Large and abrupt excursions of Ti/Ca ratios are observed in both cores, but are significantly better defined in the southern core, representative of Nordeste conditions. In this core there are a total of 9 Ti/Ca excursions, the oldest recovered dating to ~98ka. These excursions correlate well with Heinrich events from the North Atlantic. High-resolution stable oxygen isotopic analysis and Mg/Ca paleothermometry undertaken on the near-surface-dwelling planktic foraminiferal species Globierinoides ruber provide a picture of paleoceanographic forcings in the western equatorial Atlantic. The northern and southern cores respectively exhibit rapid warming of ~3C and ~3.5C between the last glacial maximum and the early Holocene. Furthermore, in almost all cases, during the last glacial stage, there was a 0.5C to 2C warming of the western equatorial Atlantic during the periods of high Ti/Ca ratios that correlate with Heinrich events. Thus, as observed in some previous studies, the western equatorial Atlantic was warm and the adjacent southern tropical continent was wet at the same time that the high-latitude North Atlantic was cold. The largely accepted paradigm is that Northern hemisphere cold events result in a southward migration of the Intertropical Convergence Zone (ITCZ), contributing to drier conditions at the northern extent of the ITCZ annual range (Cariaco Basin) and increased precipitation in the southern tropics of South America. The ITCZ appears to have been influenced by millennial variability of

  11. North Atlantic-Fennoscandian Holocene climate trends and mechanisms

    NARCIS (Netherlands)

    Sejrup, H.P.; Seppä, H.; McKay, N.; Kaufman, D.S.; Geirsdottir, A.; de Vernal, A.; Renssen, H.; Husum, K.; Jennings, A.; Andrews, J.T.

    2016-01-01

    To investigate the mechanisms behind Holocene regional climate trends from north of 58°N in the North Atlantic-Fennoscandian region Principal Component Analysis (PCA) was performed and a temperature anomaly stack produced from 81 proxy derived summer temperature time series from 74 sites. The PC

  12. Influence of North Atlantic modes on European climate extremes

    Science.gov (United States)

    Proemmel, K.; Cubasch, U.

    2017-12-01

    It is well known that the North Atlantic strongly influences European climate. Only few studies exist that focus on its impact on climate extremes. We are interested in these extremes and the processes and mechanisms behind it. For the analysis of the North Atlantic Oscillation (NAO) we use simulations performed with the Max Planck Institute for Meteorology Earth System Model (MPI-ESM). The NAO has a strong impact especially on European winter and the changes in minimum temperature are even larger than in maximum temperature. The impact of the Atlantic Multi-decadal Variability (AMV) on climate extremes is analyzed in ECHAM6 simulations forced with AMV warm and AMV cold sea surface temperature patterns. We analyze different extreme indices and try to understand the processes.

  13. Salinity Trends within the Upper Layers of the Subpolar North Atlantic

    Science.gov (United States)

    Tesdal, J. E.; Abernathey, R.; Goes, J. I.; Gordon, A. L.; Haine, T. W. N.

    2017-12-01

    Examination of a range of salinity products collectively suggest widespread freshening of the North Atlantic from the mid-2000 to the present. Monthly salinity fields reveal negative trends that differ in magnitude and significance between western and eastern regions of the North Atlantic. These differences can be attributed to the large negative interannual excursions in salinity in the western subpolar gyre and the Labrador Sea, which are not apparent in the central or eastern subpolar gyre. This study demonstrates that temporal trends in salinity in the northwest (including the Labrador Sea) are subject to mechanisms that are distinct from those responsible for the salinity trends in central and eastern North Atlantic. In the western subpolar gyre a negative correlation between near surface salinity and the circulation strength of the subpolar gyre suggests that negative salinity anomalies are connected to an intensification of the subpolar gyre, which is causing increased flux of freshwater from the East Greenland Current and subsequent transport into the Labrador Sea during the melting season. Analyses of sea surface wind fields suggest that the strength of the subpolar gyre is linked to the North Atlantic Oscillation and Arctic Oscillation-driven changes in wind stress curl in the eastern subpolar gyre. If this trend of decreasing salinity continues, it has the potential to enhance water column stratification, reduce vertical fluxes of nutrients and cause a decline in biological production and carbon export in the North Atlantic Ocean.

  14. First record of giant anteater (xenarthra, myrmecophagidae) in north america.

    Science.gov (United States)

    Shaw, C A; McDonald, H G

    1987-04-10

    A right metacarpal III represents the first North American record of the giant anteater (Myrmecophaga tridactyla). Recovered in northwestern Sonora, Mexico, with a rich vertebrate fauna of early Pleistocene (Irvingtonian) age, it belongs to a cohort of large mammals that dispersed from South America to North America along a savanna corridor. Presumably habitat and climatic changes have subsequently driven this mammalian family more than 3000 kilometers back into Central America from its former expansion into temperate North America.

  15. Toxaphene in minke whales (Balaenoptera acutorostrata) from the North Atlantic

    International Nuclear Information System (INIS)

    Gouteux, B.; Muir, D.C.G.; Backus, S.; Born, E.W.; Dietz, R.; Haug, T.; Metcalfe, T.; Metcalfe, C.; Oien, N.

    2008-01-01

    Toxaphene contamination of minke whales (Balaenoptera acutorostrata) from North Atlantic waters was examined for the first time. Total toxaphene and ΣCHB (sum of 11 chlorobornanes) concentrations in blubber samples ranged from 170 ± 110 and 41 ± 39 ng/g lipid weight (l.w.) for female minke whales from southeastern Greenland to 5800 ± 4100 and 1100 ± 780 ng/g l.w. for males from the North Sea, respectively. Very large variations in toxaphene concentrations among sampling areas were observed suggesting a spatial segregation of minke whales. However, much of the apparent geographical discrimination was explained by the seasonal fluctuation of animal fat mass. Patterns of CHBs in males revealed that recalcitrant CHBs were in higher proportions in animals from the more easterly areas than in animals from the more westerly areas. This trend may be influenced by the predominance of the US, over the European, input of toxaphene to North Atlantic waters. - High levels of toxaphene were found in different sub-populations of minke whales from North Atlantic waters

  16. Toxaphene in minke whales (Balaenoptera acutorostrata) from the North Atlantic

    Energy Technology Data Exchange (ETDEWEB)

    Gouteux, B. [Aquatic Ecosystem Protection Research Division, Environment Canada, Burlington, ON, L7R 4A6 (Canada); Muir, D.C.G. [Aquatic Ecosystem Protection Research Division, Environment Canada, Burlington, ON, L7R 4A6 (Canada)], E-mail: Derek.Muir@ec.gc.ca; Backus, S. [Aquatic Ecosystem Protection Research Division, Environment Canada, Burlington, ON, L7R 4A6 (Canada); Born, E.W. [Greenland Institute of Natural Resources, P.O. Box 570, DK-3900 Nuuk, Greenland (Denmark); Dietz, R. [National Environmental Research Institute, Department of Arctic Environment, Frederiksborgvej 399, P.O. Box 358, DK-4000 Roskilde (Denmark); Haug, T. [Institute of Marine Research, P.O. Box 6404, N-9294 Tromso (Norway); Metcalfe, T.; Metcalfe, C. [Worsfold Water Quality Centre, Trent University, Peterborough, ON, K9J 7B8 (Canada); Oien, N. [Institute of Marine Research, P.O. Box 1870, N-5817 Bergen (Norway)

    2008-05-15

    Toxaphene contamination of minke whales (Balaenoptera acutorostrata) from North Atlantic waters was examined for the first time. Total toxaphene and {sigma}CHB (sum of 11 chlorobornanes) concentrations in blubber samples ranged from 170 {+-} 110 and 41 {+-} 39 ng/g lipid weight (l.w.) for female minke whales from southeastern Greenland to 5800 {+-} 4100 and 1100 {+-} 780 ng/g l.w. for males from the North Sea, respectively. Very large variations in toxaphene concentrations among sampling areas were observed suggesting a spatial segregation of minke whales. However, much of the apparent geographical discrimination was explained by the seasonal fluctuation of animal fat mass. Patterns of CHBs in males revealed that recalcitrant CHBs were in higher proportions in animals from the more easterly areas than in animals from the more westerly areas. This trend may be influenced by the predominance of the US, over the European, input of toxaphene to North Atlantic waters. - High levels of toxaphene were found in different sub-populations of minke whales from North Atlantic waters.

  17. Dispersion in North Atlantic Deep Water transfer between the northern source region and the South Atlantic

    Energy Technology Data Exchange (ETDEWEB)

    Huhn, Oliver; Roether, Wolfgang [Institut fuer Umweltphysik, Universitaet Bremen (Germany)

    2007-07-01

    North Atlantic Deep Water (NADW) represents the Atlantic part of the deep, southward return arm of the oceanic 'conveyor belt', which moderates Europe's climate and effects most of the water transfer from the ocean surface into the deep waters globally. The transfer starts from the NADW formation regions, which in the case of upper NADW (approx. 1500-2000 m depth) is the Labrador Sea (far NW Atlantic). NADW is found concentrated toward the continental slope of the Americas, but subject to meandering, and to recirculation into, and mixing with, the waters of the interior Atlantic. Individual water parcels thus follow a complex ensemble of trajectories. We have obtained characteristics of that ensemble by fitting the free parameters of a suitable function using extensive observations of the transient tracers CFC-11, CFC-12, CCl{sub 4}, and tritium. A tracer transfer function of ocean-surface concentrations to those in newly formed NADW was derived as a precursory step. In the upper NADW we obtain RMS transfer-time dispersions on the way from the Labrador Sea of 31 years at 6 N rising to 53 years at 20 S, compared to mean transfer times ranging 46 to 79 years ({+-}20 %); furthermore, approximately 10 % to 40 % of the water is old, tracer-free water admixed on the way. Similar results have been obtained for lower NADW (approx. 2500-4000 m). The combination of tritium and CFC observations is particularly suited to constrain the dispersion, since it acts on the concentrations of these tracers in an opposite way. The tracer-adjusted transfer functions allow quantification of the NADW transport of pollutants and other compounds delivered to the NADW formation region. The results can furthermore check mean transfer times and large-scale dispersion of the NADW part of dynamic ocean circulation models.

  18. Coherent changes of wintertime surface air temperatures over North Asia and North America.

    Science.gov (United States)

    Yu, Bin; Lin, Hai

    2018-03-29

    The surface temperature variance and its potential change with global warming are most prominent in winter over Northern Hemisphere mid-high latitudes. Consistent wintertime surface temperature variability has been observed over large areas in Eurasia and North America on a broad range of time scales. However, it remains a challenge to quantify where and how the coherent change of temperature anomalies occur over the two continents. Here we demonstrate the coherent change of wintertime surface temperature anomalies over North Asia and the central-eastern parts of North America for the period from 1951 to 2015. This is supported by the results from the empirical orthogonal function analysis of surface temperature and temperature trend anomalies over the Northern Hemisphere extratropical lands and the timeseries analysis of the regional averaged temperature anomalies over North Asia and the Great Plains and Great Lakes. The Asian-Bering-North American (ABNA) teleconnection provides a pathway to connect the regional temperature anomalies over the two continents. The ABNA is also responsible for the decadal variation of the temperature relationship between North Asia and North America.

  19. Temperature fluctuations in the Atlantic Ocean

    International Nuclear Information System (INIS)

    Hjoello, Solfrid Saetre

    2005-01-01

    The article discusses the temperature fluctuations in connection with drought in Africa, the climate in North America, the European heat waves and the frequent tropical hurricanes in the Atlantic Ocean. Problems with climate modelling and some pollution aspects are mentioned

  20. The influence of boreal biomass burning emissions on the distribution of tropospheric ozone over North America and the North Atlantic during 2010

    Science.gov (United States)

    Parrington, M.; Palmer, P. I.; Henze, D. K.; Tarasick, D. W.; Hyer, E. J.; Owen, R. C.; Helmig, D.; Clerbaux, C.; Bowman, K. W.; Deeter, M. N.; Barratt, E. M.; Coheur, P.-F.; Hurtmans, D.; Jiang, Z.; George, M.; Worden, J. R.

    2012-02-01

    We have analysed the sensitivity of the tropospheric ozone distribution over North America and the North Atlantic to boreal biomass burning emissions during the summer of 2010 using the GEOS-Chem 3-D global tropospheric chemical transport model and observations from in situ and satellite instruments. We show that the model ozone distribution is consistent with observations from the Pico Mountain Observatory in the Azores, ozonesondes across Canada, and the Tropospheric Emission Spectrometer (TES) and Infrared Atmospheric Sounding Instrument (IASI) satellite instruments. Mean biases between the model and observed ozone mixing ratio in the free troposphere were less than 10 ppbv. We used the adjoint of GEOS-Chem to show the model ozone distribution in the free troposphere over Maritime Canada is largely sensitive to NOx emissions from biomass burning sources in Central Canada, lightning sources in the central US, and anthropogenic sources in the eastern US and south-eastern Canada. We also used the adjoint of GEOS-Chem to evaluate the Fire Locating And Monitoring of Burning Emissions (FLAMBE) inventory through assimilation of CO observations from the Measurements Of Pollution In The Troposphere (MOPITT) satellite instrument. The CO inversion showed that, on average, the FLAMBE emissions needed to be reduced to 89% of their original values, with scaling factors ranging from 12% to 102%, to fit the MOPITT observations in the boreal regions. Applying the CO scaling factors to all species emitted from boreal biomass burning sources led to a decrease of the model tropospheric distributions of CO, PAN, and NOx by as much as -20 ppbv, -50 pptv, and -20 pptv respectively. The modification of the biomass burning emission estimates reduced the model ozone distribution by approximately -3 ppbv (-8%) and on average improved the agreement of the model ozone distribution compared to the observations throughout the free troposphere, reducing the mean model bias from 5.5 to 4.0 ppbv

  1. Snow cover and temperature relationships in North America and Eurasia

    Science.gov (United States)

    Foster, J.; Owe, M.; Rango, A.

    1983-01-01

    In this study the snow cover extent during the autumn months in both North America and Eurasia has been related to the ensuing winter temperature as measured at several locations near the center of each continent. The relationship between autumn snow cover and the ensuing winter temperatures was found to be much better for Eurasia than for North America. For Eurasia the average snow cover extent during the autumn explained as much as 52 percent of the variance in the winter (December-February) temperatures compared to only 12 percent for North America. However, when the average winter snow cover was correlated with the average winter temperature it was found that the relationship was better for North America than for Eurasia. As much as 46 percent of the variance in the winter temperature was explained by the winter snow cover in North America compared to only 12 percent in Eurasia.

  2. High migration rates shape the postglacial history of amphi-Atlantic bryophytes.

    Science.gov (United States)

    Désamoré, Aurélie; Patiño, Jairo; Mardulyn, Patrick; Mcdaniel, Stuart F; Zanatta, Florian; Laenen, Benjamin; Vanderpoorten, Alain

    2016-11-01

    Paleontological evidence and current patterns of angiosperm species richness suggest that European biota experienced more severe bottlenecks than North American ones during the last glacial maximum. How well this pattern fits other plant species is less clear. Bryophytes offer a unique opportunity to contrast the impact of the last glacial maximum in North America and Europe because about 60% of the European bryoflora is shared with North America. Here, we use population genetic analyses based on approximate Bayesian computation on eight amphi-Atlantic species to test the hypothesis that North American populations were less impacted by the last glacial maximum, exhibiting higher levels of genetic diversity than European ones and ultimately serving as a refugium for the postglacial recolonization of Europe. In contrast with this hypothesis, the best-fit demographic model involved similar patterns of population size contractions, comparable levels of genetic diversity and balanced migration rates between European and North American populations. Our results thus suggest that bryophytes have experienced comparable demographic glacial histories on both sides of the Atlantic. Although a weak, but significant genetic structure was systematically recovered between European and North American populations, evidence for migration from and towards both continents suggests that amphi-Atlantic bryophyte population may function as a metapopulation network. Reconstructing the biogeographic history of either North American or European bryophyte populations therefore requires a large, trans-Atlantic geographic framework. © 2016 John Wiley & Sons Ltd.

  3. Continental outflow from the US to the upper troposphere over the North Atlantic during the NASA INTEX-NA Airborne Campaign

    Directory of Open Access Journals (Sweden)

    S. Y. Kim

    2008-04-01

    Full Text Available A case of continental outflow from the United States (US was examined using airborne measurements from NASA DC-8 flight 13 during the Intercontinental Chemical Transport Experiment – North America (INTEX-NA. Mixing ratios of methane (CH4 and carbon monoxide (CO at 8–11 km altitude over the North Atlantic were elevated to 1843 ppbv and 134 ppbv respectively, while those of carbon dioxide (CO2 and carbonyl sulfide (COS were reduced to 372.4 ppmv and 411 pptv respectively. In this region, urban and industrial influences were evidenced by elevated mixing ratios and good linear relationships between urban and industrial tracers compared to North Atlantic background air. Moreover, low mixing ratios and a good correlation between COS and CO2 showed a fingerprint of terrestrial uptake and minimal dilution during rapid transport over a 1–2 day time period. Analysis of synoptic conditions, backward trajectories, and photochemical aging estimates based on C3H8/C2H6 strongly suggested that elevated anthropogenic tracers in the upper troposphere of the flight region were the result of transport via convection and warm conveyor belt (WCB uplifting of boundary layer air over the southeastern US. This mechanism is supported by the similar slope values of linear correlations between long-lived (months anthropogenic tracers (e.g., C2Cl4 and CHCl3 from the flight region and the planetary boundary layer in the southeastern US. In addition, the aircraft measurements suggest that outflow from the US augmented the entire tropospheric column at mid-latitudes over the North Atlantic. Overall, the flight 13 data demonstrate a pervasive impact of US anthropogenic emissions on the troposphere over the North Atlantic.

  4. Do the Atlantic climate modes impact the ventilation of the eastern tropical North Atlantic oxygen minimum zones?

    Science.gov (United States)

    Burmeister, Kristin; Lübbecke, Joke F.

    2017-04-01

    Oxygen minimum zones (OMZs) exist in the upwelling regions of the eastern tropical Atlantic and Pacific at intermediate depth. They are a consequence of high biological productivity in combination with weak ventilation. The flow fields in the tropical Atlantic is characterized by Latitudinally Alternating Zonal Jets (LAZJs) with a large vertical scale. It has been suggested that LAZJs play an important role for the ventilation of the OMZ as eastward currents advect oxygen-rich waters from the western boundary towards the OMZ. In the Eastern Tropical North Atlantic (ETNA), the eastward flowing North Equatorial Undercurrent and North Equatorial Countercurrent (NECC) provide the main oxygen supply into the OMZ. Variability in the strength and location of the LAZJs is associated with oxygen variability in the ETNA OMZ. We here want to address the question whether the variability in the zonal current field can be partly attributed to the large-scale climate modes of the tropical Atlantic, namely the Atlantic zonal and meridional mode. An influence of these modes on the NECC has been found in previous studies. For the analysis we are using the output of a global ocean circulation model, in which a 1/10° nest covering the tropical Atlantic is embedded into a global 1/2° model, as well as reanalysis products and satellite data. The zonal current field and oxygen distribution from the high resolution model is compared to observational data. The location and intensity of the current bands during positive and negative phases of the Atlantic climate modes are compared by focusing on individual events and via composite analysis. Based on the results, the potential impact of the Atlantic climate modes on the ventilation of the ETNA OMZ is discussed.

  5. Seamount physiography and biology in North-East Atlantic and Mediterranean Sea

    OpenAIRE

    T. Morato; K. Ø. Kvile; G. H. Taranto; F. Tempera; B. E. Narayanaswamy; D. Hebbeln; G. Menezes; C. Wienberg; R. S. Santos; T. J. Pitcher

    2012-01-01

    This work aims at characterising the seamount physiography and biology in the OSPAR Convention limits (North-East Atlantic Ocean) and Mediterranean Sea. We first inferred potential abundance, location and morphological characteristics of seamounts, and secondly, summarized the existing biological, geological and oceanographic in-situ research, identifying examples of well-studied seamounts. Our study showed that the seamount population in the OSPAR area (North-East Atlantic) and in Mediterran...

  6. Changing statistics of storms in the North Atlantic?

    International Nuclear Information System (INIS)

    Storch, H. von; Guddal, J.; Iden, K.A.; Jonsson, T.; Perlwitz, J.; Reistad, M.; Ronde, J. de; Schmidt, H.; Zorita, E.

    1993-01-01

    Problems in the present discussion about increasing storminess in the North Atlantic area are discusesd. Observational data so far available do not indicate a change in the storm statistics. Output from climate models points to an itensified storm track in the North Atlantic, but because of the limited skill of present-day climate models in simulating high-frequency variability and regional details any such 'forecast' has to be considered with caution. A downscaling procedure which relates large-scale time-mean aspects of the state of the atmosphere and ocean to the local statistics of storms is proposed to reconstruct past variations of high-frequency variability in the atmosphere (storminess) and in the sea state (wave statistics). First results are presented. (orig.)

  7. A millennium of north-east Atlantic cod juvenile growth trajectories inferred from archaeological otoliths.

    Directory of Open Access Journals (Sweden)

    Guðbjörg Ásta Ólafsdóttir

    Full Text Available Archaeological excavations of historical fishing sites across the North Atlantic have recovered high quantities of Atlantic cod (Gadus morhua bones. In the current study we use Atlantic cod otoliths from archaeological excavations of a historical fishing sites in north-west Iceland, dated to AD 970 -AD 1910 to examine historical growth trajectories of cod. No large scale growth variations or shifts in growth patterns were observed in the current chronologies, supporting the stability of historical Atlantic cod growth trajectories. The most significant variation in growth patterns was consistent with those that have been observed in recent times, for example, reduced early juvenile growth during periods of colder ocean temperature. The current results represent a high resolution chronological record of north-east Atlantic cod growth, greatly increasing the prior temporal range of such data, thereby providing a valuable baseline for a broad range of studies on Atlantic cod growth.

  8. Differential response of continental stock complexes of Atlantic salmon (Salmo salar) to the Atlantic Multidecadal Oscillation

    Science.gov (United States)

    Friedland, Kevin D.; Shank, Burton V.; Todd, Christopher D.; McGinnity, Philip; Nye, Janet A.

    2014-05-01

    Atlantic salmon, Salmo salar, in the North Atlantic are managed as a set of population complexes distributed in North America and Europe. In recent years, these complexes have experienced reduced marine survival and many populations within the complexes are at risk, especially those at the southern ends of the species amphi-Atlantic range. Atlantic salmon is an anadromous fish dividing its life history between residence in freshwater and the marine environment. The freshwater portion of the life history includes spawning and the rearing of juveniles where in-river production has tended to be relatively stable, whereas the first year at sea, termed the post-smolt year, is characterized by more variable rates of mortality. Although their habitats are widely separated geographically along the North Atlantic seaboards, strong recruitment coherence exists between North American and European stock complexes. This recruitment coherence is correlated with ocean temperature variation associated with the Atlantic Multidecadal Oscillation (AMO). The North Atlantic Oscillation (NAO) appears to be relatively unimportant as a driver of salmon abundance. The mechanism determining the link between AMO-related thermal variation and abundance appears to differ fundamentally for the two continental stock groupings. Whereas ocean climate variability during the first springtime months of juvenile salmon migration to sea appears to be important to the survival of North American stocks, summer climate variation appears to be central to adult recruitment variation for European stocks. This contrast in seasonal effects appears to be related to the varying roles of predation pressure and size-related mortality on the continental stock complexes. The anticipated warming due to global climate change will impose thermal conditions on salmon populations outside historical context and challenge the ability of many populations to persist.

  9. North atlantic multidecadal climate variability: An investigation of dominant time scales and processes

    NARCIS (Netherlands)

    Frankcombe, L.M.|info:eu-repo/dai/nl/304829838; von der Heydt, A.S.|info:eu-repo/dai/nl/245567526; Dijkstra, H.A.|info:eu-repo/dai/nl/073504467

    2010-01-01

    The issue of multidecadal variability in the North Atlantic has been an important topic of late. It is clear that there are multidecadal variations in several climate variables in the North Atlantic, such as sea surface temperature and sea level height. The details of this variability, in particular

  10. Interdecadal North-Atlantic meridional overturning circulation variability in EC-EARTH

    Energy Technology Data Exchange (ETDEWEB)

    Wouters, Bert; Drijfhout, Sybren; Hazeleger, Wilco

    2012-12-15

    The Atlantic meridional overturning circulation (AMOC) in a 600 years pre-industrial run of the newly developed EC-EARTH model features marked interdecadal variability with a dominant time-scale of 50-60 years. An oscillation of approximately 2 Sverdrup (1 Sv = 10{sup 6} m{sup 3} s{sup -1}) is identified, which manifests itself as a monopole causing the overturning to simultaneously strengthen (/weaken) and deepen (/shallow) as a whole. Eight years before the AMOC peaks, density in the Labrador-Irminger Sea region reaches a maximum, triggering deep water formation. This density change is caused by a counterclockwise advection of temperature and salinity anomalies at lower latitudes, which we relate to the north-south excursions of the subpolar-subtropical gyre boundary and variations in strength and position of the subpolar gyre and the North Atlantic Current. The AMOC fluctuations are not directly forced by the atmosphere, but occur in a delayed response of the ocean to forcing by the North Atlantic Oscillation, which initiates ''intergyre''-gyre fluctuations. Associated with the AMOC is a 60-year sea surface temperature variability in the Atlantic, with a pattern and timescale showing similarities with the real-world Atlantic Multidecadal Variability. This good agreement with observations lends a certain degree of credibility that the mechanism that is described in this article could be seen as representative of the real climate system. (orig.)

  11. Quantifying the influence of boreal biomass burning emissions on tropospheric oxidant chemistry over the North Atlantic using BORTAS measurements

    Science.gov (United States)

    Parrington, Mark; Palmer, Paul I.; Rickard, Andrew; Young, Jennifer; Lewis, Ally; Lee, James; Henze, Daven; Tarasick, David; Hyer, Edward; Yantosca, Robert; Bowman, Kevin; Worden, John; Griffin, Debora; Franklin, Jonathan; Helmig, Detlev

    2013-04-01

    We use the GEOS-Chem chemistry transport model to quantify the impact of boreal biomass burning on tropospheric oxidant chemistry over the North Atlantic region during summer of 2011. The GEOS-Chem model is used at a spatial resolution of 1/2 degree latitude by 2/3 degree longitude for a domain covering eastern North America, the North Atlantic Ocean and western Europe. We initialise the model with biomass burning emissions from the Fire Locating and Monitoring of Burning Emissions (FLAMBE) inventory and use a modified chemical mechanism providing a detailed description of ozone photochemistry in boreal biomass burning outflow derived from the Master Chemical Mechanism (MCM). We evaluate the 3-D model distribution of ozone and tracers associated with biomass burning against measurements made by the UK FAAM BAe-146 research aircraft, ozonesondes, ground-based and satellite instruments as part of the BORTAS experiment between 12 July and 3 August 2011. We also use the GEOS-Chem model adjoint to fit the model to BORTAS measurements to analyse the sensitivity of the model chemical mechanism and ozone distribution to wildfire emissions in central Canada.

  12. Solar wind: A possible factor driving the interannual sea surface temperature tripolar mode over North Atlantic

    Science.gov (United States)

    Xiao, Ziniu; Li, Delin

    2016-06-01

    The effect of solar wind (SW) on the North Atlantic sea surface temperature (SST) in boreal winter is examined through an analysis of observational data during 1964-2013. The North Atlantic SSTs show a pronounced meridional tripolar pattern in response to solar wind speed (SWS) variations. This pattern is broadly similar to the leading empirical orthogonal function (EOF) mode of interannual variations in the wintertime SSTs over North Atlantic. The time series of this leading EOF mode of SST shows a significant interannual period, which is the same as that of wintertime SWS. This response also appears as a compact north-south seesaw of sea level pressure and a vertical tripolar structure of zonal wind, which simultaneously resembles the North Atlantic Oscillation (NAO) in the overlying atmosphere. As compared with the typical low SWS winters, during the typical high SWS winters, the stratospheric polar night jet (PNJ) is evidently enhanced and extends from the stratosphere to the troposphere, even down to the North Atlantic Ocean surface. Notably, the North Atlantic Ocean is an exclusive region in which the SW signal spreads downward from the stratosphere to the troposphere. Thus, it seems that the SW is a possible factor for this North Atlantic SST tripolar mode. The dynamical process of stratosphere-troposphere coupling, together with the global atmospheric electric circuit-cloud microphysical process, probably accounts for the particular downward propagation of the SW signal.

  13. Elemental composition of air masses under different altitudes in Azores, central north Atlantic

    International Nuclear Information System (INIS)

    Vieira, B.J.; Wolterbeek, H.Th.

    2012-01-01

    Between 8th July 2002 and 18th June 2004, aerosol samples were collected in Azores. Their inorganic composition was obtained by neutron activation analysis in order to study the differences of aerosols in two atmospheric altitudes of the central north Atlantic: (1) PICO-NARE observatory (Lower Free Troposphere-LFT) at Pico mountain summit (38,470 deg N, 28,404 deg W, 2,225 m a.s.l.) in Pico Island, Azores, where air masses from the surrounding continents (Africa, Europe, Central and North America) pass through, carrying aerosols with anthropogenic (Sb, Br, Mo, U, Se and Tb) and/or natural emissions (Fe, Co, La, Na, Sm, Cr, Zn, Hf, K and Th); (2) TERCEIRA-NARE station (Marine Boundary Layer) at Serreta (38,69 deg N, 27,36 deg W, 50 m a.s.l.), in Terceira Island, Azores, where natural aerosols (I, Cl, Na, Br and other soil related elements) are predominant. However, a combined interpretation of the data points out to a co-existence of the anthropogenic elements Sb and Mo, eventually with similar origins as the ones passing Pico Mountain summit. Very high concentrations and enrichment factors for Sb, Mo and Br in LFT, higher than the ones found in other areas, confirm atmospheric long-range transport mainly from the west boundary of north Atlantic; this may indicate eventual accumulation and persistence of those elements in the area due to the presence of Azores high pressures or the Hadley cells effect. A significant correlation between Fe and Yb and the enrichment of rare earth elements (La, Sm, Tb and Yb) and Th in LFT aerosols, both reflect a mineral dust intrusions from north Africa (Sahara and Sahel region). (author)

  14. Reconstruction of the North Atlantic end-member of the Atlantic Meridional Overturning Circulation over glacial-interglacial cycles

    Science.gov (United States)

    Kim, J.; Seguí, M. J.; Knudson, K. P.; Yehudai, M.; Goldstein, S. L.; Pena, L. D.; Basak, C.; Ferretti, P.

    2017-12-01

    North Atlantic Deep Water (NADW) represents the major water mass that drives the Atlantic Meridional Ocean Circulation (AMOC), which undergoes substantial reorganization with changing climate. In order to understand its impact on ocean circulation and climate through time, it is necessary to constrain its composition. We report Nd isotope ratios of Fe-Mn oxide encrusted foraminifera and fish debris from DSDP Site 607 (41.00N 32.96W, 3427m), in the present-day core of NADW, and ODP 1063 (33.68N 57.62W, 4585m), on the deep abyssal plain at the interface between NADW and Antarctic Bottom Water. We provide a new North Atlantic paleocirculation record covering 2 Ma. At Site 607 interglacial ɛNd-values are consistently similar to present-day NADW (ɛNd -13.5), with median ɛNd-values of -14.3 in the Early Pleistocene and -13.8 in the Late Pleistocene. Glacial ɛNd-values are higher by 1 ɛNd-unit in the Early Pleistocene, and 1.5-2 ɛNd-units in the Late Pleistocene. Site 1063 shows much greater variability, with ɛNd ranging from -10 to -26. We interpret the North Atlantic AMOC source as represented by the Site 607 interglacial ɛNd-values, which has remained nearly stable throughout the entire period. The higher glacial ɛNd-values reflect incursions of some southern-sourced waters to Site 607, which is supported by coeval shifts to lower benthic foraminiferal d13C. In contrast, the Site 1063 ɛNd-values do not appear to reflect the AMOC end-member, and likely reflects local effects from a bottom source. A period of greatly disrupted ocean circulation marks 950-850 Ma, which may have been triggered by enhanced ice growth in the Northern Hemisphere that began around 1.2 Ma, as suggested by possible input events of Nd from the surrounding cratons into the North Atlantic observed in Site 607. Interglacial AMOC only recovers to the previously observed vigor over 200 ka following the disruption, whereas further intensified SSW incursion into the deep North Atlantic come to

  15. The late Wisconsinan and Holocene record of Walrus (Odobenus rosmarus) from North America: A review with new data from Arctic and Atlantic Canada

    Science.gov (United States)

    Dyke, A.S.; Hooper, J.; Harington, C.R.; Savelle, J.M.

    1999-01-01

    The Late Wisconsinan and Holocene record of the Atlantic walrus is known from numerous collections of bones and tusks from Arctic Canada and south to North Carolina, as well as from many archaeological sites in the Arctic and Subarctic. In contrast, the Pacific walrus has no dated Late Wisconsinan or early Holocene record in North America, and it may have been displaced into the northwest Pacific at Last Glacial Maximum (LGM). The Atlantic walrus rapidly exploited newly deglaciated territory, moving northward from its LGM refugium and reaching the Bay of Fundy by 12800 B.P., the Grand Banks by 12500 B.P., southern Labrador by 11500 B.P., and the central Canadian Arctic Archipelago (CAA) by 9700 B.P. Its southern range limit may have retracted to the Bay of Fundy by ca. 7500 B.P. Within the CAA, walrus remains cluster in two main age groups: 9700 to 8500 B.P. and 5000 to 4/3000 B.P. This pattern strongly resembles the distribution of bowhead whale radiocarbon ages from the same area, which suggests a common control by sea-ice conditions. Walrus remains occur in Indian culture archaeological sites as old as 7500 B.P. and, in some cases (Namu, British Columbia, and Mackinac Island, Michigan), they evidently represent long-distance human transport. They are much more common in Paleoeskimo and Neoeskimo culture sites. However, they occur in very low abundances, and generally as debitage, in sites older than Dorset (2500 B.P.). The walrus, therefore, may not have been hunted by early Paleoeskimos. Beginning with Early Dorset, walrus remains occur in definite diet-related contexts. Middle Dorset (2300 to 1500 B.P.) and late Thule (High Arctic, and there may be a similar gap in the middle Pre-Dorset (3400 to 2600 B.P.). Sea-ice conditions at these times may have adversely affected availability of walrus and other marine mammal resources. Walrus is a prominent faunal element in Middle Dorset sites on the Labrador coast; this is consistent with a southward displacement of

  16. Interannual variability of north Atlantic Sea surface temperatures

    International Nuclear Information System (INIS)

    Bhatt, U.S.; Battisiti, D.S.; Alexander, M.A.

    1994-01-01

    In the midlatitude north Atlantic Ocean the pattern of sea surface temperature anomalies (ssta) is characterized by a north-south dipole. Bjerknes was the first to propose that the banded structure was associated with the interannual variability. Recently, these patterns have been studied more extensively. In this study the quantitative aspects of these patterns are examined through the use of a mixed-layer model (MLM)

  17. A seasonal diary of phytoplankton in the North Atlantic

    DEFF Research Database (Denmark)

    Lindemann, Christian; St. John, Michael

    2014-01-01

    In recent years new biological and physical controls have been suggested to drive phytoplankton bloom dynamics in the North Atlantic. A better understanding of the mechanisms driving primary production has potentially important implications for the understanding of the biological carbon pump...... are not mutually exclusive, but rather complementary. Thus, moving beyond the “single mechanism” point of view, here we present an integrated conceptual model of the physical and biological controls on phytoplankton dynamics in the North Atlantic. Further we believe that the acclimation of physiological rates can...... play an important role in mediating phytoplankton dynamics. Thus, this view emphasizes the occurrence of multiple controls and relates their variations in impact to climate change...

  18. Synoptic-scale analysis of mechanisms driving surface chlorophyll dynamics in the North Atlantic

    Directory of Open Access Journals (Sweden)

    A. S. A. Ferreira

    2015-06-01

    Full Text Available Several hypotheses have been proposed for the onset of the spring phytoplankton bloom in the North Atlantic. Our main objective is to examine which bottom-up processes can best predict the annual increase in surface phytoplankton concentration in the North Atlantic by applying novel phenology algorithms to ocean colour data. We construct indicator fields and time series which, in various combinations, provide models consistent with the principle dynamics previously proposed. Using a multimodel inference approach, we investigate the evidence supporting these models and how it varies in space. We show that, in terms of bottom-up processes alone, there is a dominant physical mechanism, namely mixed-layer shoaling, that best predicts the interannual variation in the initial increase in surface chlorophyll across large sectors of the North Atlantic. We further show that different regions are governed by different physical phenomena and that wind-driven mixing is a common component, with either heat flux or light as triggers. We believe these findings to be relevant to the ongoing discussion on North Atlantic bloom onset.

  19. North Atlantic migratory bird flyways provide routes for intercontinental movement of avian influenza viruses

    Science.gov (United States)

    Dusek, Robert J.; Hallgrimsson, Gunnar T.; Ip, Hon S.; Jónsson, Jón E.; Sreevatsan, Srinand; Nashold, Sean W.; TeSlaa, Joshua L.; Enomoto, Shinichiro; Halpin, Rebecca A.; Lin, Xudong; Federova, Nadia; Stockwell, Timothy B.; Dugan, Vivien G.; Wentworth, David E.; Hall, Jeffrey S.

    2014-01-01

    Avian influenza virus (AIV) in wild birds has been of increasing interest over the last decade due to the emergence of AIVs that cause significant disease and mortality in both poultry and humans. While research clearly demonstrates that AIVs can move across the Pacific or Atlantic Ocean, there has been no data to support the mechanism of how this occurs. In spring and autumn of 2010 and autumn of 2011 we obtained cloacal swab samples from 1078 waterfowl, gulls, and shorebirds of various species in southwest and west Iceland and tested them for AIV. From these, we isolated and fully sequenced the genomes of 29 AIVs from wild caught gulls (Charadriiformes) and waterfowl (Anseriformes) in Iceland. We detected viruses that were entirely (8 of 8 genomic segments) of American lineage, viruses that were entirely of Eurasian lineage, and viruses with mixed American-Eurasian lineage. Prior to this work only 2 AIVs had been reported from wild birds in Iceland and only the sequence from one segment was available in GenBank. This is the first report of finding AIVs of entirely American lineage and Eurasian lineage, as well as reassortant viruses, together in the same geographic location. Our study demonstrates the importance of the North Atlantic as a corridor for the movement of AIVs between Europe and North America.

  20. Seamount physiography and biology in the north-east Atlantic and Mediterranean Sea

    OpenAIRE

    Morato, T.; Kvile, K. Ø.; Taranto, G. H.; Tempera, F.; Narayanaswamy, B. E.; Hebbeln, D.; Menezes, G. M.; Wienberg, C.; Santos, R. S.; Pitcher, T. J.

    2013-01-01

    This work aims at characterising the seamount physiography and biology in the OSPAR Convention limits (north-east Atlantic Ocean) and Mediterranean Sea. We first inferred potential abundance, location and morphological characteristics of seamounts, and secondly, summarized the existing biological, geological and oceanographic in situ research, identifying examples of well-studied seamounts. Our study showed that the seamount population in the OSPAR area (north-east Atlantic) and in the Medite...

  1. Mechanisms of the atmospheric response to North Atlantic multidecadal variability: a model study

    Energy Technology Data Exchange (ETDEWEB)

    Msadek, Rym [Universite Pierre et Marie Curie-Paris 6, LOCEAN/IPSL, Paris Cedex 05 (France); Princeton University, GFDL/NOAA, AOS Program, Princeton, NJ (United States); Frankignoul, Claude [Universite Pierre et Marie Curie-Paris 6, LOCEAN/IPSL, Paris Cedex 05 (France); Li, Laurent Z.X. [Universite Pierre et Marie Curie-Paris 6, LMD/IPSL, Paris Cedex 05 (France)

    2011-04-15

    The atmospheric circulation response to decadal fluctuations of the Atlantic meridional overturning circulation (MOC) in the IPSL climate model is investigated using the associated sea surface temperature signature. A SST anomaly is prescribed in sensitivity experiments with the atmospheric component of the IPSL model coupled to a slab ocean. The prescribed SST anomaly in the North Atlantic is the surface signature of the MOC influence on the atmosphere detected in the coupled simulation. It follows a maximum of the MOC by a few years and resembles the model Atlantic multidecadal oscillation. It is mainly characterized by a warming of the North Atlantic south of Iceland, and a cooling of the Nordic Seas. There are substantial seasonal variations in the geopotential height response to the prescribed SST anomaly, with an East Atlantic Pattern-like response in summer and a North Atlantic oscillation-like signal in winter. In summer, the response of the atmosphere is global in scale, resembling the climatic impact detected in the coupled simulation, albeit with a weaker amplitude. The zonally asymmetric or eddy part of the response is characterized by a trough over warm SST associated with changes in the stationary waves. A diagnostic analysis with daily data emphasizes the role of transient-eddy forcing in shaping and maintaining the equilibrium response. We show that in response to an intensified MOC, the North Atlantic storm tracks are enhanced and shifted northward during summer, consistent with a strengthening of the westerlies. However the anomalous response is weak, which suggests a statistically significant but rather modest influence of the extratropical SST on the atmosphere. The winter response to the MOC-induced North Atlantic warming is an intensification of the subtropical jet and a southward shift of the Atlantic storm track activity, resulting in an equatorward shift of the polar jet. Although the SST anomaly is only prescribed in the Atlantic ocean

  2. The influence of boreal biomass burning emissions on the distribution of tropospheric ozone over North America and the North Atlantic during 2010

    Directory of Open Access Journals (Sweden)

    M. Parrington

    2012-02-01

    Full Text Available We have analysed the sensitivity of the tropospheric ozone distribution over North America and the North Atlantic to boreal biomass burning emissions during the summer of 2010 using the GEOS-Chem 3-D global tropospheric chemical transport model and observations from in situ and satellite instruments. We show that the model ozone distribution is consistent with observations from the Pico Mountain Observatory in the Azores, ozonesondes across Canada, and the Tropospheric Emission Spectrometer (TES and Infrared Atmospheric Sounding Instrument (IASI satellite instruments. Mean biases between the model and observed ozone mixing ratio in the free troposphere were less than 10 ppbv. We used the adjoint of GEOS-Chem to show the model ozone distribution in the free troposphere over Maritime Canada is largely sensitive to NOx emissions from biomass burning sources in Central Canada, lightning sources in the central US, and anthropogenic sources in the eastern US and south-eastern Canada. We also used the adjoint of GEOS-Chem to evaluate the Fire Locating And Monitoring of Burning Emissions (FLAMBE inventory through assimilation of CO observations from the Measurements Of Pollution In The Troposphere (MOPITT satellite instrument. The CO inversion showed that, on average, the FLAMBE emissions needed to be reduced to 89% of their original values, with scaling factors ranging from 12% to 102%, to fit the MOPITT observations in the boreal regions. Applying the CO scaling factors to all species emitted from boreal biomass burning sources led to a decrease of the model tropospheric distributions of CO, PAN, and NOx by as much as −20 ppbv, −50 pptv, and −20 pptv respectively. The modification of the biomass burning emission estimates reduced the model ozone distribution by approximately −3 ppbv (−8% and on average improved the agreement of the model ozone distribution compared to the observations throughout the free troposphere

  3. Seamount physiography and biology in the north-east Atlantic and Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    T. Morato

    2013-05-01

    Full Text Available This work aims at characterising the seamount physiography and biology in the OSPAR Convention limits (north-east Atlantic Ocean and Mediterranean Sea. We first inferred potential abundance, location and morphological characteristics of seamounts, and secondly, summarized the existing biological, geological and oceanographic in situ research, identifying examples of well-studied seamounts. Our study showed that the seamount population in the OSPAR area (north-east Atlantic and in the Mediterranean Sea is large with around 557 and 101 seamount-like features, respectively. Similarly, seamounts occupy large areas of about 616 000 km2 in the OSPAR region and of about 89 500 km2 in the Mediterranean Sea. The presence of seamounts in the north-east Atlantic has been known since the late 19th century, but overall knowledge regarding seamount ecology and geology is still relatively poor. Only 37 seamounts in the OSPAR area (3.5% of all seamounts in the region, 22 in the Mediterranean Sea (9.2% of all seamounts in the region and 25 in the north-east Atlantic south of the OSPAR area have in situ information. Seamounts mapped in both areas are in general very heterogeneous, showing diverse geophysical characteristics. These differences will likely affect the biological diversity and production of resident and associated organisms.

  4. North-South precipitation patterns in western North America on interannual-to-decadal timescales

    Science.gov (United States)

    Dettinger, M.D.; Cayan, D.R.; Diaz, Henry F.; Meko, D.M.

    1998-01-01

    The overall amount of precipitation deposited along the West Coast and western cordillera of North America from 25??to 55??N varies from year to year, and superimposed on this domain-average variability are varying north-south contrasts on timescales from at least interannual to interdecadal. In order to better understand the north-south precipitation contrasts, their interannual and decadal variations are studied in terms of how much they affect overall precipitation amounts and how they are related to large-scale climatic patterns. Spatial empirical orthogonal functions (EOFs) and spatial moments (domain average, central latitude, and latitudinal spread) of zonally averaged precipitation anomalies along the westernmost parts of North America are analyzed, and each is correlated with global sea level pressure (SLP) and sea surface temperature series, on interannual (defined here as 3-7 yr) and decadal (>7 yr) timescales. The interannual band considered here corresponds to timescales that are particularly strong in tropical climate variations and thus is expected to contain much precipitation variability that is related to El Nino-Southern Oscillation; the decadal scale is defined so as to capture the whole range of long-term climatic variations affecting western North America. Zonal EOFs of the interannual and decadal filtered versions of the zonal-precipitation series are remarkably similar. At both timescales, two leading EOFs describe 1) a north-south seesaw of precipitation pivoting near 40??N and 2) variations in precipitation near 40??N, respectively. The amount of overall precipitation variability is only about 10% of the mean and is largely determined by precipitation variations around 40??-45??N and most consistently influenced by nearby circulation patterns; in this sense, domain-average precipitation is closely related to the second EOF. The central latitude and latitudinal spread of precipitation distributions are strongly influenced by precipitation

  5. Clitopilus argentinus in North America

    NARCIS (Netherlands)

    Baroni, Timothy J.

    1992-01-01

    Clitopilus argentinus is reported for the first time from North America. A full description and illustrations of the basidiomata and microscopic structures are provided. An X-ray elemental analysis of the diagnostic ‘hyaline’ incrustations of the pileus surface shows these extracellular structures

  6. Postglacial viability and colonization in North America's ice-free corridor

    DEFF Research Database (Denmark)

    Pedersen, Mikkel W.; Ruter, Anthony; Schweger, Charles

    2016-01-01

    During the Last Glacial Maximum, continental ice sheets isolated Beringia (northeast Siberia and northwest North America) from unglaciated North America. By around 15 to 14 thousand calibrated radiocarbon years before present (cal. kyr BP), glacial retreat opened an approximately 1,500-km...

  7. Late Holocene Drought Variability in Eastern North America: Evidence From the Peatland Archive

    Science.gov (United States)

    Booth, R. K.; Jackson, S. T.

    2006-12-01

    conditions throughout the western Great Lakes region. These include a large drought event during the late 16th century and a series of widespread drought events between 1900-1600 BP and 1100- 700 BP. The highest magnitude droughts of the last 2000 years occurred during an interval roughly consistent with the Medieval Warm Period (MWP), with individual drought events centered on 1000 BP, 800 BP, and 700 BP. These droughts were associated with major ecological changes, including abrupt changes in vegetation and fire regime. Tree-ring records from the western United States also document a series of extensive and high-magnitude drought events during this time period, suggesting these droughts affected a large portion of mid-latitude North America. Similarly widespread drought during the last 100 years has been linked to sea surface temperature (SST) anomalies in the adjacent ocean basins, particularly an anomalously warm North Atlantic and mid-latitude Pacific, and an anomalously cold Tropical Pacific. We hypothesize that the widespread droughts apparent in our bog records were related to amplification of a similar spatial mode of moisture variability. Comparison with available proxy SST records provides some support for this hypothesis, although a more extensive network of terrestrial hydroclimate records, derived using consistent methods and proxies, needs to be used in conjunction with the developing network of proxy SST records to fully test this hypothesis.

  8. Regional nitrogen budgets and riverine N & P fluxes for the drainages to the North Atlantic Ocean: Natural and human influences

    Science.gov (United States)

    Howarth, R.W.; Billen, G.; Swaney, D.; Townsend, A.; Jaworski, N.; Lajtha, K.; Downing, J.A.; Elmgren, Ragnar; Caraco, N.; Jordan, T.; Berendse, F.; Freney, J.; Kudeyarov, V.; Murdoch, P.; Zhu, Z.-L.

    1996-01-01

    We present estimates of total nitrogen and total phosphorus fluxes in rivers to the North Atlantic Ocean from 14 regions in North America, South America, Europe, and Africa which collectively comprise the drainage basins to the North Atlantic. The Amazon basin dominates the overall phosphorus flux and has the highest phosphorus flux per area. The total nitrogen flux from the Amazon is also large, contributing 3.3 Tg yr-1 out of a total for the entire North Atlantic region of 13.1 Tg yr-1. On a per area basis, however, the largest nitrogen fluxes are found in the highly disturbed watersheds around the North Sea, in northwestern Europe, and in the northeastern U.S., all of which have riverine nitrogen fluxes greater than 1,000 kg N km-2 yr-1. Non-point sources of nitrogen dominate riverine fluxes to the coast in all regions. River fluxes of total nitrogen from the temperate regions of the North Atlantic basin are correlated with population density, as has been observed previously for fluxes of nitrate in the world's major rivers. However, more striking is a strong linear correlation between river fluxes of total nitrogen and the sum of anthropogenically-derived nitrogen inputs to the temperate regions (fertilizer application, human-induced increases in atmospheric deposition of oxidized forms of nitrogen, fixation by leguminous crops, and the import/export of nitrogen in agricultural products). On average, regional nitrogen fluxes in rivers are only 25% of these anthropogenically derived nitrogen inputs. Denitrification in wetlands and aquatic ecosystems is probably the dominant sink, with storage in forests perhaps also of importance. Storage of nitrogen in groundwater, although of importance in some localities, is a very small sink for nitrogen inputs in all regions. Agricultural sources of nitrogen dominate inputs in many regions, particularly the Mississippi basin and the North Sea drainages. Deposition of oxidized nitrogen, primarily of industrial origin, is the

  9. Interannual variability of western North Pacific SST anomalies and its impact on North Pacific and North America

    Science.gov (United States)

    Park, Jae-Heung; An, Soon-Il; Kug, Jong-Seong

    2017-12-01

    In this study, the interannual variability of sea surface temperature (SST) and its atmospheric teleconnection over the western North Pacific (WNP) toward the North Pacific/North America during boreal winter are investigated. First, we defined the WNP mode as the first empirical orthogonal function (EOF) mode of SST anomalies over the WNP region (100-165°E, 0-35°N), of which the principle component time-series are significantly correlated with several well-known climate modes such as the warm pool mode which is the second EOF mode of the tropical to North Pacific SST anomalies, North Pacific oscillation (NPO), North Pacific gyre oscillation (NPGO), and central Pacific (CP)-El Niño at 95% confidence level, but not correlated with the eastern Pacific (EP)-El Niño. The warm phase of the WNP mode (sea surface warming) is initiated by anomalous southerly winds through reduction of wind speed with the background of northerly mean winds over the WNP during boreal winter, i.e., reduced evaporative cooling. Meanwhile, the atmospheric response to the SST warming pattern and its diabatic heating further enhance the southerly wind anomaly, referred to the wind-evaporation-SST (WES) feedback. Thus, the WNP mode is developed and maintained through winter until spring, when the northerly mean wind disappears. Furthermore, it is also known that anomalous upper-level divergence associated with WNP mode leads to the NPO-like structure over the North Pacific and the east-west pressure contrast pattern over the North America through Rossby wave propagation, impacting the climate over the North Pacific and North America.

  10. Timing of migratory baleen whales at the Azores in relation to the North Atlantic spring bloom

    NARCIS (Netherlands)

    Visser, F.; Hartman, K.L.; Pierce, G.J.; Valavanis, V.D.; Huisman, J.

    2011-01-01

    Each year, a phytoplankton spring bloom starts just north of the North Atlantic Subtropical Gyre, and then expands northwards across the entire North Atlantic. Here, we investigate whether the timing of the spring migration of baleen whales is related to the timing of the phytoplankton spring bloom,

  11. Interannual variations and future change of wintertime extratropical cyclone activity over North America in CCSM3

    Energy Technology Data Exchange (ETDEWEB)

    Teng, Haiyan; Washington, Warren M.; Meehl, Gerald A. [National Center for Atmospheric Research, PO Box 3000, Boulder, CO (United States)

    2008-06-15

    Climatology and interannual variations of wintertime extratropical cyclone frequency in CCSM3 twentieth century simulation are compared with the NCEP/NCAR reanalysis during 1950-1999. CCSM3 can simulate the storm tracks reasonably well, although the model produces slightly less cyclones at the beginning of the Pacific and Atlantic storm tracks and weaker poleward deflection over the Pacific. As in the reanalysis, frequency of cyclones stronger than 980 hPa shows significant correlation with the Pacific/North America (PNA) teleconnection pattern over the Pacific region and with the North Atlantic Oscillation (NAO) in the Atlantic sector. Composite maps are constructed for opposite phases of El Nino-Southern Oscillation (ENSO) and the NAO and all anomalous patterns coincide with observed. One CCSM3 twenty-first century A1B scenario realization indicates there is significant increase in the extratropical cyclone frequency on the US west coast and decrease in Alaska. Meanwhile, cyclone frequency increases from the Great Lakes region to Quebec and decreases over the US east coast, suggesting a possible northward shift of the Atlantic storm tracks under the warmer climate. The cyclone frequency anomalies are closely linked to changes in seasonal mean states of the upper-troposphere zonal wind and baroclinicity in the lower troposphere. Due to lack of 6-hourly outputs, we cannot apply the cyclone-tracking algorithm to the other eight CCSM3 realizations. Based on the linkage between the mean state change and the cyclone frequency anomalies, it is likely a common feature among the other ensemble members that cyclone activity is reduced on the East Coast and in Alaska as a result of global warming. (orig.)

  12. Arctic climatechange and its impacts on the ecology of the North Atlantic.

    Science.gov (United States)

    Greene, Charles H; Pershing, Andrew J; Cronin, Thomas M; Ceci, Nicole

    2008-11-01

    Arctic climate change from the Paleocene epoch to the present is reconstructed with the objective of assessing its recent and future impacts on the ecology of the North Atlantic. A recurring theme in Earth's paleoclimate record is the importance of the Arctic atmosphere, ocean, and cryosphere in regulating global climate on a variety of spatial and temporal scales. A second recurring theme in this record is the importance of freshwater export from the Arctic in regulating global- to basin-scale ocean circulation patterns and climate. Since the 1970s, historically unprecedented changes have been observed in the Arctic as climate warming has increased precipitation, river discharge, and glacial as well as sea-ice melting. In addition, modal shifts in the atmosphere have altered Arctic Ocean circulation patterns and the export of freshwater into the North Atlantic. The combination of these processes has resulted in variable patterns of freshwater export from the Arctic Ocean and the emergence of salinity anomalies that have periodically freshened waters in the North Atlantic. Since the early 1990s, changes in Arctic Ocean circulation patterns and freshwater export have been associated with two types of ecological responses in the North Atlantic. The first of these responses has been an ongoing series of biogeographic range expansions by boreal plankton, including renewal of the trans-Arctic exchanges of Pacific species with the Atlantic. The second response was a dramatic regime shift in the shelf ecosystems of the Northwest Atlantic that occurred during the early 1990s. This regime shift resulted from freshening and stratification of the shelf waters, which in turn could be linked to changes in the abundances and seasonal cycles of phytoplankton, zooplankton, and higher trophic-level consumer populations. It is predicted that the recently observed ecological responses to Arctic climate change in the North Atlantic will continue into the near future if current trends

  13. Vertical slab sinking and westward subduction offshore of Mesozoic North America

    Science.gov (United States)

    Sigloch, Karin; Mihalynuk, Mitchell G.

    2013-04-01

    Subducted slabs in the mantle, as imaged by seismic tomography, preserve a record of ancient subduction zones. Ongoing debate concerns how direct this link is. How long ago did each parcel of slab subduct, and where was the trench located relative to the imaged slab position? Resolving these questions will benefit paleogeographic reconstructions, and restrict the range of plausible rheologies for mantle convection simulations. We investigate one of the largest and best-constrained Mesozoic slab complexes, the "Farallon" in the transition zone and lower mantle beneath North America. We quantitatively integrate observations from whole-mantle P-wave tomography, global plate reconstructions, and land geological evidence from the North American Cordillera. These three data sets permit us to test the simplest conceivable hypothesis for linking slabs to paleo-trenches: that each parcel of slab sank only vertically shortly after entering the trench That is, we test whether within the limits of tomographic resolution, all slab material lies directly below the location where it subducted beneath its corresponding arc. Crucially and in contrast to previous studies, we do not accept or impose an Andean-style west coast trench (Farallon-beneath-continent subduction) since Jurassic times, as this scenario is inconsistent with many geological observations. Slab geometry alone suggests that trenches started out as intra-oceanic because tomography images massive, linear slab "walls" in the lower mantle, extending almost vertically from about 800 km to 2000+ km depth. Such steep geometries would be expected from slabs sinking vertically beneath trenches that were quasi-stationary over many tens of millions of years. Intra-oceanic trenches west of Mesozoic North America could have been stationary, whereas a coastal Farallon trench could not, because the continent moved westward continuously as the Atlantic opened. Overlap of North American west-coast positions, as reconstructed in a

  14. Post-Glacial Development of Western North Atlantic - Labrador Sea Oceanographic Circulation

    DEFF Research Database (Denmark)

    Sheldon, Christina

    2015-01-01

    The subpolar North Atlantic Ocean – Labrador Sea region is an important site for both oceanographic and atmospheric circulation. The convergence of ocean currents causes downwelling of cold, saline water in the subpolar gyre, helping to drive the world-wide thermohaline circulation system. The main......, the subpolar gyre weakened, which carried less Gulf Stream-derived water to the western North Atlantic Ocean via the West Greenland Current and the Slopewater Current, south of Newfoundland. Changes in the subpolar gyre circulation had developed to be analogous to the modern climate by approximately 2 cal kyr...... surface currents involved in the gyre are the south-flowing, cold and relatively fresh Labrador Current and the north-flowing, warm and relatively saline Gulf Stream. The oceanic front between these two major currents moves north and south, dependent on the relative strengths of the currents, impacting...

  15. Deformation in D″ Beneath North America From Anisotropy

    Science.gov (United States)

    Nowacki, A. J.; Wookey, J.; Kendall, J. M.

    2009-12-01

    The lowermost few hundred kilometres of the Earth's mantle—known as D″—form the boundary between it and the core below, control the Earth's convective system, and are the site of probable large thermochemical heterogeneity. Seismic observations of D″ show a strong heterogeneity in seismic wave velocity and significant seismic anisotropy (the variation of wave speed with direction) are present in many parts of the region. On the basis of continuous regions of fast shear velocity (VS) anomalies in global models, it is also proposed as the resting place of subducted slabs, notably the Farallon beneath North America. A phase change of MgSiO3-perovskite (pv) to a post-perovskite (ppv) structure at near-core-mantle boundary (CMB) conditions is a compelling mechanism to explain the seismic features of D″. An outstanding question is how this and other mineral phases may deform to produce anisotropy, with different mechanisms possible. With knowledge either of mantle flow or which slip system is responsible for causing deformation, we can potentially determine the other with observations of the resulting seismic anisotropy. We investigate the dynamics at the CMB beneath North America using differential shear wave splitting in S and ScS phases from earthquakes of magnitude MW>5.5 in South and Central America, Hawaii the Mid-Atlantic Ridge and East Pacific Rise. They are detected on ~500 stations in North America, giving ~700 measurements of anisotropy in D″. We achieve this by correcting for anisotropy in the upper mantle (UM) beneath both the source and receiver. The measurements cover three regions beneath western USA, the Yucatan peninsula and Florida. In each case, two different, crossing ray paths are used, so that the style of anisotropy can be constrained—a single azimuth cannot distinguish differing cases. Our results showing ~1% anisotropy dependent on azimuth are not consistent with transverse isotropy with a vertical symmetry axis (VTI) anywhere. The

  16. Cones, Seeds, and Foliage of Tetraclinis Salicornioides (Cupressaceae) from the Oligocene and Miocene of Western North America: A Geographic Extension of the European Tertiary Species.

    Science.gov (United States)

    Kvacek; Manchester; Schorn

    2000-03-01

    The cupressaceous genus Tetraclinis is recognized from the Oligocene and Miocene of western North America on the basis of co-occurring seed cones, seeds, and foliage branches. Morphological and anatomical comparisons with the two previously recognized European Tertiary species indicate that the North American specimens are morphologically inseparable from Tetraclinis salicornioides (Unger) Kvacek. The North American taxon is treated as a new variety, T. salicornioides (Unger) Kvacek var. praedecurrens (Knowlton) comb. et stat. nov., and is distinguished from the European representatives, T. salicornioides (Unger) Kvacek var. salicornioides, by slight anatomical differences in the leaf epidermis. Although cones and seeds of the fossil species are closely similar to those of extant Tetraclinis articulata, the foliage is more "spreading," composed of flattened segments with fused facial and lateral leaves that are apparently adaptive for a more mesic climate. The recognition of T. salicornioides in western North America along with the absence of Tetraclinis in the fossil and recent flora of eastern Asia provide evidence for communication of the species across the North Atlantic during the early or middle Tertiary.

  17. A hierarchical classification of freshwater mussel diversity in North America

    Science.gov (United States)

    Wendell R. Haag

    2010-01-01

    Aim North America harbours the most diverse freshwater mussel fauna on Earth. This fauna has high endemism at the continental scale and within individual river systems. Previous faunal classifications for North America were based on intuitive, subjective assessments of species distributions, primarily the occurrence of endemic species, and do not portray continent-wide...

  18. Fingerprinting North Atlantic water masses near Iceland using Nd-isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Frank, Norbert [Institut fuer Umweltphysik, INF229, Heidelberg (Germany); Waldner, Astrid [Paul Scherrer Institute, Villigen (Switzerland); Montagna, Paolo [CNR - ISMAR, Bologna (Italy); Colin, Christophe [IDES, Universite de Paris-Sud, Orsay (France); Wu, Qiong [State Key Laboratory, Tongji University, Shanghai (China)

    2015-07-01

    The radiogenic {sup 143}Nd/{sup 144}Nd ratio of seawater is a valuable tracer of north Atlantic circulation pathways, driven by continental runoff (freshwater and Aeolian dust), boundary exchange and advection and thus mixing patterns. A region of particular interest in the North Atlantic is the overflow across the Iceland-Scotland Ridge injecting water from the Arctic Ocean into the Iceland basin (Iceland Scotland Overflow Water). However, Iceland itself constitutes a local source for Nd due to possible leaching of young volcanic basalts adding radiogenic {sup 143}Nd/{sup 144}Nd to seawater. We have conducted an intense survey of physical properties and Nd-isotope composition between Iceland and the Azores that allows to fingerprint different water masses of the North Atlantic through the {sup 143}Nd/{sup 144}Nd ratio and that demonstrates the very local influence of volcanic material to the seawater Nd cycle. A first local transect is achieved from the open ocean to the outflow of the Vatnajoekull glacier. Runoff influences seawater Nd in close vicinity (< 40 km near the outflow). A along shelf transect provide a similar observation. From Iceland to the Azores, however, water masses of the sub-tropical and sub-polar gyre are clearly distinguishable.

  19. 77 FR 16538 - Endangered and Threatened Species; Initiation of 5-Year Review for the North Atlantic Right Whale...

    Science.gov (United States)

    2012-03-21

    ... and Threatened Species; Initiation of 5-Year Review for the North Atlantic Right Whale and the North Pacific Right Whale AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric...: NMFS announces a 5-year review of North Atlantic right whale (Eubalaena glacialis) and North Pacific...

  20. Regional seesaw between the North Atlantic and Nordic Seas during the last glacial abrupt climate events

    Directory of Open Access Journals (Sweden)

    M. Wary

    2017-06-01

    Full Text Available Dansgaard–Oeschger oscillations constitute one of the most enigmatic features of the last glacial cycle. Their cold atmospheric phases have been commonly associated with cold sea-surface temperatures and expansion of sea ice in the North Atlantic and adjacent seas. Here, based on dinocyst analyses from the 48–30 ka interval of four sediment cores from the northern Northeast Atlantic and southern Norwegian Sea, we provide direct and quantitative evidence of a regional paradoxical seesaw pattern: cold Greenland and North Atlantic phases coincide with warmer sea-surface conditions and shorter seasonal sea-ice cover durations in the Norwegian Sea as compared to warm phases. Combined with additional palaeorecords and multi-model hosing simulations, our results suggest that during cold Greenland phases, reduced Atlantic meridional overturning circulation and cold North Atlantic sea-surface conditions were accompanied by the subsurface propagation of warm Atlantic waters that re-emerged in the Nordic Seas and provided moisture towards Greenland summit.

  1. Trans-Pacific and trans-Arctic pathways of the intertidal macroalga Fucus distichus L. reveal multiple glacial refugia and colonizations from the North Pacific to the North Atlantic

    NARCIS (Netherlands)

    Coyer, James A.; Hoarau, Galice; Van Schaik, Jaap; Luijckx, Pepijn; Olsen, Jeanine L.

    Aim We examined the phylogeography of the cold-temperate macroalgal species Fucus distichus L., a key foundation species in rocky intertidal shores and the only Fucus species to occur naturally in both the North Pacific and the North Atlantic. Location North Pacific and North Atlantic oceans (42

  2. How the Subpolar gyre strength influences phytoplankton blooms dynamics in the North Atlantic

    DEFF Research Database (Denmark)

    Ferreira, Ana Sofia; Payne, Mark; MacKenzie, Brian

    2012-01-01

    height (SSH, from the AVISO project) as a proxy of current strength. Three regions were strategically chosen to characterize positions relative to the NASPG, describing: region 1—the northern part of NASPG, including the Irminger Current (IC); region 2—the North Atlantic Current (NAC), its northwards......Changes in the North Atlantic Subpolar gyre (NASPG) have been linked to the interannual variability of primary production. However, little is known about the mechanisms behind both environmental processes, and how the NASPG strength may extend its potential impacts to higher trophic levels......, including early life stages of commercial fish species. We assess NASPG strength effect on North Atlantic phytoplankton bloom dynamics. We analyse time‐series (from 1998 to 2010) of chlorophyll a (Chl a, from the Globcolour project) annual anomaly as a proxy of phytoplankton abundance, and of sea surface...

  3. The North Atlantic Ocean as habitat for Calanus finmarchicus: Environmental factors and life history traits

    Science.gov (United States)

    Melle, Webjørn; Runge, Jeffrey; Head, Erica; Plourde, Stéphane; Castellani, Claudia; Licandro, Priscilla; Pierson, James; Jonasdottir, Sigrun; Johnson, Catherine; Broms, Cecilie; Debes, Høgni; Falkenhaug, Tone; Gaard, Eilif; Gislason, Astthor; Heath, Michael; Niehoff, Barbara; Nielsen, Torkel Gissel; Pepin, Pierre; Stenevik, Erling Kaare; Chust, Guillem

    2014-12-01

    Here we present a new, pan-Atlantic compilation and analysis of data on Calanus finmarchicus abundance, demography, dormancy, egg production and mortality in relation to basin-scale patterns of temperature, phytoplankton biomass, circulation and other environmental characteristics in the context of understanding factors determining the distribution and abundance of C. finmarchicus across its North Atlantic habitat. A number of themes emerge: (1) the south-to-north transport of plankton in the northeast Atlantic contrasts with north-to-south transport in the western North Atlantic, which has implications for understanding population responses of C. finmarchicus to climate forcing, (2) recruitment to the youngest copepodite stages occurs during or just after the phytoplankton bloom in the east whereas it occurs after the bloom at many western sites, with up to 3.5 months difference in recruitment timing, (3) the deep basin and gyre of the southern Norwegian Sea is the centre of production and overwintering of C. finmarchicus, upon which the surrounding waters depend, whereas, in the Labrador/Irminger Seas production mainly occurs along the margins, such that the deep basins serve as collection areas and refugia for the overwintering populations, rather than as centres of production, (4) the western North Atlantic marginal seas have an important role in sustaining high C. finmarchicus abundance on the nearby coastal shelves, (5) differences in mean temperature and chlorophyll concentration between the western and eastern North Atlantic are reflected in regional differences in female body size and egg production, (6) regional differences in functional responses of egg production rate may reflect genetic differences between western and eastern populations, (7) dormancy duration is generally shorter in the deep waters adjacent to the lower latitude western North Atlantic shelves than in the east, (8) there are differences in stage-specific daily mortality rates between

  4. 78 FR 61844 - North Atlantic Coast Comprehensive Study

    Science.gov (United States)

    2013-10-04

    ...: The U.S. Army Corps of Engineers (USACE) is requesting peer reviewed information that would be useful in the preparation of the North Atlantic Coast Comprehensive Study (Hurricane Sandy). The USACE is... information by electronic mail to: [email protected] . Please include your name and contact information in...

  5. Field Evaluations of Topical Arthropod Repellents in North, Central, and South America

    Science.gov (United States)

    2014-09-01

    De La Rocque et al. 2011) and their spread into higher elevations of Africa, Latin America , and Asia (Epstein 2001). Dengue fever and...denguehemorrhagic fever have resurgeddramatically in Latin America (Zell 2004). In North America ,West Nile virus has impacted signiÞcantly the health and welfare of...VECTOR CONTROL, PEST MANAGEMENT, RESISTANCE, REPELLENTS Field Evaluations of Topical Arthropod Repellents in North, Central , and South America KENDRA

  6. A new era for uranium mining in North America

    International Nuclear Information System (INIS)

    Poissonet, M.; Marvy, A.

    1997-01-01

    North America will be one of the few places in the world where continuous development of new uranium mining projects and renewed, more intense exploration will occur for the coming years. Although the present project approval process and regulatory regime can be seen as a burden, past discoveries of world-class deposits have made North America the best place to invest in uranium production for many years to come. (author) 1 fig

  7. ATLANTIC BATS: a data set of bat communities from the Atlantic Forests of South America.

    Science.gov (United States)

    Muylaert, Renata D L; Stevens, Richard D; Esbérard, Carlos E L; Mello, Marco A R; Garbino, Guilherme S T; Varzinczak, Luiz H; Faria, Deborah; Weber, Marcelo D M; Kerches Rogeri, Patricia; Regolin, André L; Oliveira, Hernani F M D; Costa, Luciana D M; Barros, Marília A S; Sabino-Santos, Gilberto; Crepaldi de Morais, Mara Ariane; Kavagutti, Vinicius S; Passos, Fernando C; Marjakangas, Emma-Liina; Maia, Felipe G M; Ribeiro, Milton C; Galetti, Mauro

    2017-12-01

    Bats are the second most diverse mammal order and they provide vital ecosystem functions (e.g., pollination, seed dispersal, and nutrient flux in caves) and services (e.g., crop pest suppression). Bats are also important vectors of infectious diseases, harboring more than 100 different virus types. In the present study, we compiled information on bat communities from the Atlantic Forests of South America, a species-rich biome that is highly threatened by habitat loss and fragmentation. The ATLANTIC BATS data set comprises 135 quantitative studies carried out in 205 sites, which cover most vegetation types of the tropical and subtropical Atlantic Forest: dense ombrophilous forest, mixed ombrophilous forest, semideciduous forest, deciduous forest, savanna, steppe, and open ombrophilous forest. The data set includes information on more than 90,000 captures of 98 bat species of eight families. Species richness averaged 12.1 per site, with a median value of 10 species (ranging from 1 to 53 species). Six species occurred in more than 50% of the communities: Artibeus lituratus, Carollia perspicillata, Sturnira lilium, Artibeus fimbriatus, Glossophaga soricina, and Platyrrhinus lineatus. The number of captures divided by sampling effort, a proxy for abundance, varied from 0.000001 to 0.77 individuals·h -1 ·m -2 (0.04 ± 0.007 individuals·h -1 ·m -2 ). Our data set reveals a hyper-dominance of eight species that together that comprise 80% of all captures: Platyrrhinus lineatus (2.3%), Molossus molossus (2.8%), Artibeus obscurus (3.4%), Artibeus planirostris (5.2%), Artibeus fimbriatus (7%), Sturnira lilium (14.5%), Carollia perspicillata (15.6%), and Artibeus lituratus (29.2%). © 2017 by the Ecological Society of America.

  8. Atlantic continental margin of the United States

    Science.gov (United States)

    Grow, John A.; Sheridan, Robert E.; Palmer, A.R.

    1982-01-01

    The objective of this Decade of North American Geology (D-NAG) volume will be to focus on the Mesozoic and Cenozoic evolution of the U.S. Atlantic continental margin, including the onshore coastal plain, related onshore Triassic-Jurassic rift grabens, and the offshore basins and platforms. Following multiple compressional tectonic episodes between Africa and North America during the Paleozoic Era that formed the Appalachian Mountains, the Mesozoic and Cenozoic Eras were dominated by tensional tectonic processes that separated Africa and North America. Extensional rifting during Triassic and Early Jurassic times resulted in numerous tensional grabens both onshore and offshore, which filled with nonmarine continental red beds, lacustrine deposits, and volcanic flows and debris. The final stage of this breakup between Africa and North America occurred beneath the present outer continental shelf and continental slope during Early or Middle Jurassic time when sea-floor spreading began to form new oceanic crust and lithosophere between the two continents as they drifted apart. Postrift subsidence of the marginal basins continued in response to cooling of the lithosphere and sedimentary loading.Geophysical surveys and oil-exploration drilling along the U.S. Atlantic continental margin during the past 5 years are beginning to answer many questions concerning its deep structure and stratigraphy and how it evolved during the rifting and early sea-floor-spreading stages of the separation of this region from Africa. Earlier geophysical studies of the U.S. continental margin used marine refraction and submarine gravity measurements. Single-channel seismic-reflection, marine magnetic, aeromagnetic, and continuous gravity measurements became available during the 1960s.

  9. A Review of ENSO Influence on the North Atlantic. A Non-Stationary Signal

    Directory of Open Access Journals (Sweden)

    Belén Rodríguez-Fonseca

    2016-06-01

    Full Text Available The atmospheric seasonal cycle of the North Atlantic region is dominated by meridional movements of the circulation systems: from the tropics, where the West African Monsoon and extreme tropical weather events take place, to the extratropics, where the circulation is dominated by seasonal changes in the jetstream and extratropical cyclones. Climate variability over the North Atlantic is controlled by various mechanisms. Atmospheric internal variability plays a crucial role in the mid-latitudes. However, El Niño-Southern Oscillation (ENSO is still the main source of predictability in this region situated far away from the Pacific. Although the ENSO influence over tropical and extra-tropical areas is related to different physical mechanisms, in both regions this teleconnection seems to be non-stationary in time and modulated by multidecadal changes of the mean flow. Nowadays, long observational records (greater than 100 years and modeling projects (e.g., CMIP permit detecting non-stationarities in the influence of ENSO over the Atlantic basin, and further analyzing its potential mechanisms. The present article reviews the ENSO influence over the Atlantic region, paying special attention to the stability of this teleconnection over time and the possible modulators. Evidence is given that the ENSO–Atlantic teleconnection is weak over the North Atlantic. In this regard, the multidecadal ocean variability seems to modulate the presence of teleconnections, which can lead to important impacts of ENSO and to open windows of opportunity for seasonal predictability.

  10. Groundwater availability in the Atlantic Coastal Plain of North and South Carolina

    Science.gov (United States)

    Campbell, Bruce G.; Coes, Alissa L.

    2010-01-01

    The Atlantic Coastal Plain aquifers and confining units of North and South Carolina are composed of crystalline carbonate rocks, sand, clay, silt, and gravel and contain large volumes of high-quality groundwater. The aquifers have a long history of use dating back to the earliest days of European settlement in the late 1600s. Although extensive areas of some of the aquifers have or currently (2009) are areas of groundwater level declines from large-scale, concentrated pumping centers, large areas of the Atlantic Coastal Plain contain substantial quantities of high-quality groundwater that currently (2009) are unused. Groundwater use from the Atlantic Coastal Plain aquifers in North Carolina and South Carolina has increased during the past 60 years as the population has increased along with demands for municipal, industrial, and agricultural water needs. While North Carolina and South Carolina work to increase development of water supplies in response to the rapid growth in these coastal populations, both States recognize that they are facing a number of unanswered questions regarding availability of groundwater supplies and the best methods to manage these important supplies. An in-depth assessment of groundwater availability of the Atlantic Coastal Plain aquifers of North and South Carolina has been completed by the U.S. Geological Survey Groundwater Resources Program. This assessment includes (1) a determination of the present status of the Atlantic Coastal Plain groundwater resources; (2) an explanation for how these resources have changed over time; and (3) development of tools to assess the system's response to stresses from potential future climate variability. Results from numerous previous investigations of the Atlantic Coastal Plain by Federal and State agencies have been incorporated into this effort. The primary products of this effort are (1) comprehensive hydrologic datasets such as groundwater levels, groundwater use, and aquifer properties; (2) a

  11. The role of the subtropical North Atlantic water cycle in recent US extreme precipitation events

    Science.gov (United States)

    Li, Laifang; Schmitt, Raymond W.; Ummenhofer, Caroline C.

    2018-02-01

    The role of the oceanic water cycle in the record-breaking 2015 warm-season precipitation in the US is analyzed. The extreme precipitation started in the Southern US in the spring and propagated northward to the Midwest and the Great Lakes in the summer of 2015. This seasonal evolution of precipitation anomalies represents a typical mode of variability of US warm-season precipitation. Analysis of the atmospheric moisture flux suggests that such a rainfall mode is associated with moisture export from the subtropical North Atlantic. In the spring, excessive precipitation in the Southern US is attributable to increased moisture flux from the northwestern portion of the subtropical North Atlantic. The North Atlantic moisture flux interacts with local soil moisture which enables the US Midwest to draw more moisture from the Gulf of Mexico in the summer. Further analysis shows that the relationship between the rainfall mode and the North Atlantic water cycle has become more significant in recent decades, indicating an increased likelihood of extremes like the 2015 case. Indeed, two record-high warm-season precipitation events, the 1993 and 2008 cases, both occurred in the more recent decades of the 66 year analysis period. The export of water from the North Atlantic leaves a marked surface salinity signature. The salinity signature appeared in the spring preceding all three extreme precipitation events analyzed in this study, i.e. a saltier-than-normal subtropical North Atlantic in spring followed by extreme Midwest precipitation in summer. Compared to the various sea surface temperature anomaly patterns among the 1993, 2008, and 2015 cases, the spatial distribution of salinity anomalies was much more consistent during these extreme flood years. Thus, our study suggests that preseason salinity patterns can be used for improved seasonal prediction of extreme precipitation in the Midwest.

  12. The Variation of Tropical Cyclone Rainfall within the North Atlantic and Pacific as Observed from Satellites

    Science.gov (United States)

    Rodgers, Edward; Pierce, Harold; Adler, Robert

    1999-01-01

    Tropical cyclone monthly rainfall amounts are estimated from passive microwave satellite observations in the North Atlantic and in three equal geographical regions of the North Pacific (i.e., Western, Central, and Eastern North Pacific). These satellite-derived rainfall amounts are used to assess the impact of tropical cyclone rainfall in altering the geographical, seasonal, and inter-annual distribution of the 1987-1989, 1991-1998 North Atlantic and Pacific rainfall during June-November when tropical cyclones are most abundant. To estimate these tropical cyclone rainfall amounts, mean monthly rain rates are derived from the Defence Meteorological Satellite Program (DMSP) Special Sensor Microwave/ Radiometer (SSM/I) observations within 444 km radius of the center of those North Atlantic and Pacific tropical cyclones that reached storm stage and greater. These rain rate observations are then multiplied by the number of hours in a given month. Mean monthly rainfall amounts are also constructed for all the other North Atlantic and Pacific raining systems during this eleven year period for the purpose of estimating the geographical distribution and intensity of rainfall contributed by non-tropical cyclone systems. Further, the combination of the non-tropical cyclone and tropical cyclone (i.e., total) rainfall is constructed to delineate the fractional amount that tropical cyclones contributed to the total North Pacific rainfall.

  13. East Greenland Ridge in the North Atlantic Ocean

    DEFF Research Database (Denmark)

    Andreasen, Arne Døssing; Dahl-Jensen, T.; Thybo, Hans

    2008-01-01

    The combined Greenland-Senja Fracture Zones (GSFZ) represent a first-order plate tectonic feature in the North Atlantic Ocean. The GSFZ defines an abrupt change in the character of magnetic anomalies with well-defined seafloor spreading anomalies in the Greenland and Norwegian basins to the south...... but ambiguous and weak magnetic anomalies in the Boreas Basin to the north. Substantial uncertainty exists concerning the plate tectonic evolution of the latter area, including the role of the East Greenland Ridge, which is situated along the Greenland Fracture Zone. In 2002, a combined ocean-bottom seismometer...

  14. Forest Health Status in North America

    Directory of Open Access Journals (Sweden)

    Borys Tkacz

    2007-01-01

    Full Text Available The forests of North America provide a variety of benefits including water, recreation, wildlife habitat, timber, and other forest products. However, they continue to face many biotic and abiotic stressors including fires, native and invasive pests, fragmentation, and air pollution. Forest health specialists have been monitoring the health of forests for many years. This paper highlights some of the most damaging forest stressors affecting North American forests in recent years and provides some projections of future risks.

  15. Rat Lungworm Expands into North America

    Centers for Disease Control (CDC) Podcasts

    2016-01-21

    Emily York, integrated pest management specialist at the Sam Noble Museum of Natural History, discusses the rat lungworm expansion in North America.  Created: 1/21/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 1/21/2016.

  16. Impact of the Winter North Pacific Oscillation on the Surface Air Temperature over Eurasia and North America: Sensitivity to the Index Definition

    Science.gov (United States)

    Chen, Shangfeng; Song, Linye

    2018-06-01

    This study analyzes the impact of the winter North Pacific Oscillation (NPO) on the surface air temperature (SAT) variations over Eurasia and North America based on six different NPO indices. Results show that the influences of the winter NPO on the SAT over Eurasia and North America are sensitive to the definition of the NPO index. The impact of the winter NPO on the SAT variations over Eurasia (North America) is significant (insignificant) when the anticyclonic anomaly associated with the NPO index over the North Pacific midlatitudes shifts westward and pronounced northerly wind anomalies appear around Lake Baikal. By contrast, the impact of the winter NPO on the SAT variations over Eurasia (North America) is insignificant (significant) when the anticyclonic anomaly over the North Pacific related to the NPO index shifts eastward and the associated northerly wind anomalies to its eastern flank extend to North America. The present study suggests that the NPO definition should be taken into account when analyzing the impact of the winter NPO on Eurasian and North American SAT variations.

  17. On which timescales do gas transfer velocities control North Atlantic CO2 flux variability?

    Science.gov (United States)

    Couldrey, Matthew P.; Oliver, Kevin I. C.; Yool, Andrew; Halloran, Paul R.; Achterberg, Eric P.

    2016-05-01

    The North Atlantic is an important basin for the global ocean's uptake of anthropogenic and natural carbon dioxide (CO2), but the mechanisms controlling this carbon flux are not fully understood. The air-sea flux of CO2, F, is the product of a gas transfer velocity, k, the air-sea CO2 concentration gradient, ΔpCO2, and the temperature- and salinity-dependent solubility coefficient, α. k is difficult to constrain, representing the dominant uncertainty in F on short (instantaneous to interannual) timescales. Previous work shows that in the North Atlantic, ΔpCO2 and k both contribute significantly to interannual F variability but that k is unimportant for multidecadal variability. On some timescale between interannual and multidecadal, gas transfer velocity variability and its associated uncertainty become negligible. Here we quantify this critical timescale for the first time. Using an ocean model, we determine the importance of k, ΔpCO2, and α on a range of timescales. On interannual and shorter timescales, both ΔpCO2 and k are important controls on F. In contrast, pentadal to multidecadal North Atlantic flux variability is driven almost entirely by ΔpCO2; k contributes less than 25%. Finally, we explore how accurately one can estimate North Atlantic F without a knowledge of nonseasonal k variability, finding it possible for interannual and longer timescales. These findings suggest that continued efforts to better constrain gas transfer velocities are necessary to quantify interannual variability in the North Atlantic carbon sink. However, uncertainty in k variability is unlikely to limit the accuracy of estimates of longer-term flux variability.

  18. Atmospheric multidecadal variations in the North Atlantic realm: proxy data, observations, and atmospheric circulation model studies

    Directory of Open Access Journals (Sweden)

    K. Grosfeld

    2007-01-01

    Full Text Available We investigate the spatial and temporal characteristics of multidecadal climate variability in the North Atlantic realm, using observational data, proxy data and model results. The dominant pattern of multidecadal variability of SST depicts a monopolar structure in the North Atlantic during the instrumental period with cold (warm phases during 1900–1925 and 1970–1990 (1870–1890 and 1940–1960. Two atmospheric general circulation models of different complexity forced with global SST over the last century show SLP anomaly patterns from the warm and cold phases of the North Atlantic similar to the corresponding observed patterns. The analysis of a sediment core from Cariaco Basin, a coral record from the northern Red Sea, and a long-term sea level pressure (SLP reconstruction reveals that the multidecadal mode of the atmospheric circulation characterizes climate variability also in the pre-industrial era. The analyses of SLP reconstruction and proxy data depict a persistent atmospheric mode at least over the last 300 years, where SLP shows a dipolar structure in response to monopolar North Atlantic SST, in a similar way as the models' responses do. The combined analysis of observational and proxy data with model experiments provides an understanding of multidecadal climate modes during the late Holocene. The related patterns are useful for the interpretation of proxy data in the North Atlantic realm.

  19. Impact of North Atlantic Current changes on the Nordic Seas and the Arctic Ocean

    OpenAIRE

    Kauker, Frank; Gerdes, Rüdiger; Karcher, Michael; Köberle, Cornelia

    2005-01-01

    The impact of North Atlantic Current (NAC) volume, heat, and salt transport variability onto the NordicSeas and the Arctic Ocean is investigated using numerical hindcast and sensitivity experiments. Theocean-sea ice model reproduces observed propagation pathways and speeds of SST anomalies.Part of the signal reaching the entrance to the Nordic Seas between Iceland and Scotland originatesin the lower latitude North Atlantic. Response experiments with different prescribed conditionsat 50N show ...

  20. Reconstruction of the North Atlantic tropical cyclones in Azores for the last 800 years.

    Science.gov (United States)

    Rubio-Ingles, Maria Jesus; Sánchez, Guiomar; Trigo, Ricardo; Francus, Pierre; Gonçalves, Vitor; Raposeiro, Pedro; Freitas, Conceiçao; Borges, Paolo; Hernández, Armand; Bao, Roberto; Vázquez-Loureiro, David; Andrade, Cesar; Sáez, Alberto; Giralt, Santiago

    2014-05-01

    The variability of North Atlantic tropical storms has been the focus of several studies. Duration and seasonality has been attributed to a number of climate patterns and processes such as El Niño-Southern Oscillation, Atlantic Meridional Mode, African easterly waves, and atmospheric Rossby waves, but their tracks have been widely related to the North Atlantic Oscillation. Several authors have pointed out an increase and track shifting of North Atlantic tropical cyclones since 1995 with increased probability of these turning north far away from the North American continent. However, this cannot be regarded as an infrequent phenomenon as most proxy records from the Atlantic North have shown the existence of similar patterns in the past. Sao Miguel Island (Azores archipelago, Portugal) is settled in the middle of the Atlantic Ocean. This location makes this island an excellent natural laboratory to record shifts on North Atlantic tropical storms tracks that can reach the archipelago as low intensity hurricanes (e.g. Nadine in 2012) or downgraded to tropical storm (e.g. Grace in 2009). In the present work, lake sediment records have been used as a proxy sensor of tropical storms. Lagoa Azul is located inside Sete Cidades volcanic caldera and its catchment is characterized by stepped and forested caldera walls. Tropical storms and heavy rainfalls produce a flashy and substantial enhancement in the erosion of the catchment, increasing the sediments reaching the lake by rockfalls deposits (in littoral zones) and flood events deposits (in offshore zones). These flood events can be recognized in the sedimentary record as lobe deposits dominated by terrestrial components. It can be found in the sedimentary record and the bathymetry. Instrumental meteorological data and historical records have been compiled to reconstruct the most recent history of the North Atlantic tropical storms that have landed or affected the Sao Miguel Island (Andrade et al., 2008). In addition, a 1

  1. Forcing of the wintertime atmospheric circulation by the multidecadal fluctuations of the North Atlantic ocean

    International Nuclear Information System (INIS)

    Peings, Yannick; Magnusdottir, Gudrun

    2014-01-01

    The North Atlantic sea surface temperature exhibits fluctuations on the multidecadal time scale, a phenomenon known as the Atlantic Multidecadal Oscillation (AMO). This letter demonstrates that the multidecadal fluctuations of the wintertime North Atlantic Oscillation (NAO) are tied to the AMO, with an opposite-signed relationship between the polarities of the AMO and the NAO. Our statistical analyses suggest that the AMO signal precedes the NAO by 10–15 years with an interesting predictability window for decadal forecasting. The AMO footprint is also detected in the multidecadal variability of the intraseasonal weather regimes of the North Atlantic sector. This observational evidence is robust over the entire 20th century and it is supported by numerical experiments with an atmospheric global climate model. The simulations suggest that the AMO-related SST anomalies induce the atmospheric anomalies by shifting the atmospheric baroclinic zone over the North Atlantic basin. As in observations, the positive phase of the AMO results in more frequent negative NAO—and blocking episodes in winter that promote the occurrence of cold extreme temperatures over the eastern United States and Europe. Thus, it is plausible that the AMO plays a role in the recent resurgence of severe winter weather in these regions and that wintertime cold extremes will be promoted as long as the AMO remains positive. (paper)

  2. First Detection of Bat White-Nose Syndrome in Western North America.

    Science.gov (United States)

    Lorch, Jeffrey M; Palmer, Jonathan M; Lindner, Daniel L; Ballmann, Anne E; George, Kyle G; Griffin, Kathryn; Knowles, Susan; Huckabee, John R; Haman, Katherine H; Anderson, Christopher D; Becker, Penny A; Buchanan, Joseph B; Foster, Jeffrey T; Blehert, David S

    2016-01-01

    White-nose syndrome (WNS) is an emerging fungal disease of bats caused by Pseudogymnoascus destructans. Since it was first detected near Albany, NY, in 2006, the fungus has spread across eastern North America, killing unprecedented numbers of hibernating bats. The devastating impacts of WNS on Nearctic bat species are attributed to the likely introduction of P. destructans from Eurasia to naive host populations in eastern North America. Since 2006, the disease has spread in a gradual wavelike pattern consistent with introduction of the pathogen at a single location. Here, we describe the first detection of P. destructans in western North America in a little brown bat (Myotis lucifugus) from near Seattle, WA, far from the previously recognized geographic distribution of the fungus. Whole-genome sequencing and phylogenetic analyses indicated that the isolate of P. destructans from Washington grouped with other isolates of a presumed clonal lineage from the eastern United States. Thus, the occurrence of P. destructans in Washington does not likely represent a novel introduction of the fungus from Eurasia, and the lack of intensive surveillance in the western United States makes it difficult to interpret whether the occurrence of P. destructans in the Pacific Northwest is disjunct from that in eastern North America. Although there is uncertainty surrounding the impacts of WNS in the Pacific Northwest, the presence of the pathogen in western North America could have major consequences for bat conservation. IMPORTANCE White-nose syndrome (WNS) represents one of the most consequential wildlife diseases of modern times. Since it was first documented in New York in 2006, the disease has killed millions of bats and threatens several formerly abundant species with extirpation or extinction. The spread of WNS in eastern North America has been relatively gradual, inducing optimism that disease mitigation strategies could be established in time to conserve bats susceptible

  3. New aero-gravity results from the Arctic: Linking the latest Cretaceous-early Cenozoic plate kinematics of the North Atlantic and Arctic Ocean

    DEFF Research Database (Denmark)

    Døssing, Arne; Hopper, J.R.; Olesen, Arne Vestergaard

    2013-01-01

    The tectonic history of the Arctic Ocean remains poorly resolved and highly controversial. Details regarding break up of the Lomonosov Ridge from the Barents-Kara shelf margins and the establishment of seafloor spreading in the Cenozoic Eurasia Basin are unresolved. Significantly, the plate...... tectonic evolution of the Mesozoic Amerasia Basin is essentially unknown. The Arctic Ocean north of Greenland is at a critical juncture that formed at the locus of a Mesozoic three-plate setting between the Lomonosov Ridge, Greenland, and North America. In addition, the area is close to the European plate...... plateau against an important fault zone north of Greenland. Our results provide new constraints for Cretaceous-Cenozoic plate reconstructions of the Arctic. Key Points Presentation of the largest aero-gravity survey acquired over the Arctic Ocean Plate tectonic link between Atlantic and Arctic spreading...

  4. Fostering renewable energy markets in North America

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Jeremy [North American Comission for Environmental Cooperation (CEC), (United States)

    2007-06-15

    This presentation describes projects, programs and other issues addressed in order to promote renewable energy markets in North America. These are carried out by the North American Commission for Environmental Cooperation (CEC). In the first part of this presentation, there are going to be found some of the rules imposed by the North American Agreement on Environmental Cooperation (NAAEC). Then, it is shown the structure of the CEC as well as its programs, besides, there are presented the environment projects and the objectives along with their respective trades. There are described both benefits environmental and non-environmental. Also, there are shown the issues which the CEC is working in. And finally, it is shown a list mentioning the aspects that would change if: the expansion of the Mexico's Federal Commission of Electricity (CFE), happens, the grid-interconnected and the self supply of Renewable Electricity increase. [Spanish] En esta presentacion se describen los proyectos, los programas y otras cuestiones, cuyo objetivo es impulsar los mercados de energia renovable en America del Norte, realizadas por la North American Commission for Environmental Cooperation. En la primera parte, se encuentran algunas de las reglas impuestas por el Acuerdo de Cooperacion Ambiental de America del Norte (ACAAN). Enseguida, se muestra la estructura y los programas de la Comision para la Cooperacion Ambiental (CCA). Asimismo, se describen los proyectos ambientales, los objetivos junto con sus correspondientes tratados. Mas adelante, se explican tanto los beneficios ambientales como aquellos que no lo son. Igualmente, explican las cuestiones que podrian cambiar de: suceder la expansion de la Comision Federal de Electricidad (CFE), incrementarse el auto- suministro de la energia renovable y los sistemas interconectados.

  5. North America and Asia Pacific LNG markets

    International Nuclear Information System (INIS)

    Pirie, J.D.

    1997-01-01

    The liquefied natural gas (LNG) export opportunities in the Asia Pacific market were reviewed. Some of the differences that affect a North American LNG projects compared to more typical LNG projects were also outlined. The two main aspects of the LNG market in North America include the establishment of LNG import terminals on the east and southern coasts of the United States and the development of export oriented LNG projects. The Pac-Rim LNG project calls for initial delivery to South Korea of 4.0 MTPA by the end of 2000. A large LNG project has also been proposed for the year 2005 which would use Prudhoe Bay gas. Generally, in North America, there is little use for large scale LNG import projects because of the vast pipeline network that delivers gas reliably and at low cost anywhere in North America. However, LNG remains a good alternative for the Asia Pacific region because of the lack of a pipeline network. Also, Japan, Korea and Taiwan, the three main centers for LNG demand, have no domestic energy supplies and rely on imported energy sources. China is another major market opportunity for LNG. The Pac-Rim LNG project differs from others of its kind in that usually, an LNG project is based on the availability of large reservoirs of natural gas owned by state governments and involves production agreements with multi-national oil and gas companies. This scenario is simply not possible in Canada's deregulated environment. In contrast, the existence of upstream facilities, technical expertise, and low capital costs, hence reduced risks and time to develop an LNG project, gives Canada significant advantages. 3 tabs., 3 figs

  6. Heart Failure in North America

    OpenAIRE

    Blair, John E. A; Huffman, Mark; Shah, Sanjiv J

    2013-01-01

    Heart failure is a major health problem that affects patients and healthcare systems worldwide. Within the continent of North America, differences in economic development, genetic susceptibility, cultural practices, and trends in risk factors and treatment all contribute to both inter-continental and within-continent differences in heart failure. The United States and Canada represent industrialized countries with similar culture, geography, and advanced economies and infrastructure. During t...

  7. Contrasting records of sea-level change in the eastern and western North Atlantic during the last 300 years

    Science.gov (United States)

    Long, A. J.; Barlow, N. L. M.; Gehrels, W. R.; Saher, M. H.; Woodworth, P. L.; Scaife, R. G.; Brain, M. J.; Cahill, N.

    2014-02-01

    We present a new 300-year sea-level reconstruction from a salt marsh on the Isle of Wight (central English Channel, UK) that we compare to other salt-marsh and long tide-gauge records to examine spatial and temporal variability in sea-level change in the North Atlantic. Our new reconstruction identifies an overall rise in relative sea level (RSL) of c. 0.30 m since the start of the eighteenth century at a rate of 0.9±0.3 mm yr. Error-in-variables changepoint analysis indicates that there is no statistically significant deviation from a constant rate within the dataset. The reconstruction is broadly comparable to other tide-gauge and salt-marsh records from the European Atlantic, demonstrating coherence in sea level in this region over the last 150-300 years. In contrast, we identify significant differences in the rate and timing of RSL with records from the east coast of North America. The absence of a strong late 19th/early 20th century RSL acceleration contrasts with that recorded in salt marsh sediments along the eastern USA coastline, in particular in a well-dated and precise sea-level reconstruction from North Carolina. This suggests that this part of the North Carolina sea level record represents a regionally specific sea level acceleration. This is significant because the North Carolina record has been used as if it were globally representative within semi-empirical parameterisations of past and future sea-level change. We conclude that regional-scale differences of sea-level change highlight the value of using several, regionally representative RSL records when calibrating and testing semi-empirical models of sea level against palaeo-records. This is because by using records that potentially over-estimate sea-level rise in the past such models risk over-estimating sea-level rise in the future.

  8. Adult Education Faculty and Programs in North America

    Science.gov (United States)

    Tisdell, Elizabeth J.; Wright, Robin Redmon; Taylor, Edward W.

    2016-01-01

    This article reports on the findings of a quantitative survey of North American adult education faculty and a textual analysis of websites of adult education graduate programs in North America conducted in the fall of 2013. This study examined background information about adult education faculty and programs; the nature of faculty work interests,…

  9. Climate, fishery and society interactions: Observations from the North Atlantic

    Science.gov (United States)

    Hamilton, Lawrence C.

    2007-11-01

    Interdisciplinary studies comparing fisheries-dependent regions across the North Atlantic find a number of broad patterns. Large ecological shifts, disastrous to historical fisheries, have resulted when unfavorable climatic events occur atop overfishing. The "teleconnections" linking fisheries crises across long distances include human technology and markets, as well as climate or migratory fish species. Overfishing and climate-driven changes have led to a shift downwards in trophic levels of fisheries takes in some ecosystems, from dominance by bony fish to crustaceans. Fishing societies adapt to new ecological conditions through social reorganization that have benefited some people and places, while leaving others behind. Characteristic patterns of demographic change are among the symptoms of such reorganization. These general observations emerge from a review of recent case studies of individual fishing communities, such as those conducted for the North Atlantic Arc research project.

  10. A spatially explicit estimate of the prewhaling abundance of the endangered North Atlantic right whale.

    Science.gov (United States)

    Monsarrat, Sophie; Pennino, M Grazia; Smith, Tim D; Reeves, Randall R; Meynard, Christine N; Kaplan, David M; Rodrigues, Ana S L

    2016-08-01

    The North Atlantic right whale (NARW) (Eubalaena glacialis) is one of the world's most threatened whales. It came close to extinction after nearly a millennium of exploitation and currently persists as a population of only approximately 500 individuals. Setting appropriate conservation targets for this species requires an understanding of its historical population size, as a baseline for measuring levels of depletion and progress toward recovery. This is made difficult by the scarcity of records over this species' long whaling history. We sought to estimate the preexploitation population size of the North Atlantic right whale and understand how this species was distributed across its range. We used a spatially explicit data set on historical catches of North Pacific right whales (NPRWs) (Eubalaena japonica) to model the relationship between right whale relative density and the environment during the summer feeding season. Assuming the 2 right whale species select similar environments, we projected this model to the North Atlantic to predict how the relative abundance of NARWs varied across their range. We calibrated these relative abundances with estimates of the NPRW total prewhaling population size to obtain high and low estimates for the overall NARW population size prior to exploitation. The model predicted 9,075-21,328 right whales in the North Atlantic. The current NARW population is thus <6% of the historical North Atlantic carrying capacity and has enormous potential for recovery. According to the model, in June-September NARWs concentrated in 2 main feeding areas: east of the Grand Banks of Newfoundland and in the Norwegian Sea. These 2 areas may become important in the future as feeding grounds and may already be used more regularly by this endangered species than is thought. © 2015 Society for Conservation Biology.

  11. Atlantic salmon, Salmo salar L. are broadly susceptible to isolates representing the North American genogroups of infectious hematopoietic necrosis virus

    Science.gov (United States)

    Kurath, Gael; Winton, James R.; Dale, Ole B.; Purcell, Maureen K.; Falk, Knut; Busch, Robert D.

    2016-01-01

    Beginning in 1992, three epidemic waves of infectious hematopoietic necrosis, often with high mortality, occurred in farmed Atlantic salmon Salmo salar L. on the west coast of North America. We compared the virulence of eleven strains of infectious hematopoietic necrosis virus (IHNV), representing the U, M and L genogroups, in experimental challenges of juvenile Atlantic salmon in freshwater. All strains caused mortality and there was wide variation within genogroups: cumulative mortality for five U-group strains ranged from 20 to 100%, four M-group strains ranged 30-63% and two L-group strains varied from 41 to 81%. Thus, unlike Pacific salmonids, there was no apparent correlation of virulence in a particular host species with virus genogroup. The mortality patterns indicated two different phenotypes in terms of kinetics of disease progression and final per cent mortality, with nine strains having moderate virulence and two strains (from the U and L genogroups) having high virulence. These phenotypes were investigated by histopathology and immunohistochemistry to describe the variation in the course of IHNV disease in Atlantic salmon. The results from this study demonstrate that IHNV may become a major threat to farmed Atlantic salmon in other regions of the world where the virus has been, or may be, introduced.

  12. The intertropical convergence zone modulates intense hurricane strikes on the western North Atlantic margin.

    Science.gov (United States)

    van Hengstum, Peter J; Donnelly, Jeffrey P; Fall, Patricia L; Toomey, Michael R; Albury, Nancy A; Kakuk, Brian

    2016-02-24

    Most Atlantic hurricanes form in the Main Development Region between 9°N to 20°N along the northern edge of the Intertropical Convergence Zone (ITCZ). Previous research has suggested that meridional shifts in the ITCZ position on geologic timescales can modulate hurricane activity, but continuous and long-term storm records are needed from multiple sites to assess this hypothesis. Here we present a 3000 year record of intense hurricane strikes in the northern Bahamas (Abaco Island) based on overwash deposits in a coastal sinkhole, which indicates that the ITCZ has likely helped modulate intense hurricane strikes on the western North Atlantic margin on millennial to centennial-scales. The new reconstruction closely matches a previous reconstruction from Puerto Rico, and documents a period of elevated intense hurricane activity on the western North Atlantic margin from 2500 to 1000 years ago when paleo precipitation proxies suggest that the ITCZ occupied a more northern position. Considering that anthropogenic warming is predicted to be focused in the northern hemisphere in the coming century, these results provide a prehistoric analog that an attendant northern ITCZ shift in the future may again return the western North Atlantic margin to an active hurricane interval.

  13. Statistical Modelling of Fishing Activities in the North Atlantic

    NARCIS (Netherlands)

    Fernández, C.; Ley, E.; Steel, M.F.J.

    1997-01-01

    This paper deals with the issue of modeling daily catches of fishing boats in the Grand Bank fishing grounds. We have data on catches per species for a number of vessels collected by the European Union in the context of the North Atlantic Fisheries Organization. Many variables can be thought to

  14. Twentieth-century atmospheric river activity along the west coasts of Europe and North America: algorithm formulation, reanalysis uncertainty and links to atmospheric circulation patterns

    Science.gov (United States)

    Brands, S.; Gutiérrez, J. M.; San-Martín, D.

    2017-05-01

    A new atmospheric-river detection and tracking scheme based on the magnitude and direction of integrated water vapour transport is presented and applied separately over 13 regions located along the west coasts of Europe (including North Africa) and North America. Four distinct reanalyses are considered, two of which cover the entire twentieth-century: NOAA-CIRES Twentieth Century Reanalysis v2 (NOAA-20C) and ECMWF ERA-20C. Calculations are done separately for the OND and JFM-season and, for comparison with previous studies, for the ONDJFM-season as a whole. Comparing the AR-counts from NOAA-20C and ERA-20C with a running 31-year window looping through 1900-2010 reveals differences in the climatological mean and inter-annual variability which, at the start of the twentieth-century, are much more pronounced in western North America than in Europe. Correlating European AR-counts with the North Atlantic Oscillation (NAO) reveals a pattern reminiscent of the well-know precipitation dipole which is stable throughout the entire century. A similar analysis linking western North American AR-counts to the North Pacific index (NPI) is hampered by the aforementioned poor reanalysis agreement at the start of the century. During the second half of the twentieth-century, the strength of the NPI-link considerably varies with time in British Columbia and the Gulf of Alaska. Considering the period 1950-2010, AR-counts are then associated with other relevant large-scale circulation indices such as the East Atlantic, Scandinavian, Pacific-North American and West Pacific patterns (EA, SCAND, PNA and WP). Along the Atlantic coastline of the Iberian Peninsula and France, the EA-link is stronger than the NAO-link if the OND season is considered and the SCAND-link found in northern Europe is significant during both seasons. Along the west coast of North America, teleconnections are generally stronger during JFM in which case the NPI-link is significant in any of the five considered

  15. Chapter 13, Policy options: North America

    Science.gov (United States)

    Jane Barr; James Dobrowolski; John Campbell; Philippe Le Prestre; Lori Lynch; Marc Sydnor; Robert Adler; Jose Etcheverry; Alexander Kenny; Catherine Hallmich; Jim Lazar; Russell M. Meyer; Robin Newmark; Janet Peace; Julie A. Suhr Pierce; Stephen. Yamasaki

    2012-01-01

    As previously indicated, GEO-5 shifts the GEO focus from identifying environmental problems to identifying solutions that governments can then prioritize. This chapter provides examples of a number of policy options and market mechanisms that have shown some success in improving environmental conditions in North America. They are organized by priority environmental...

  16. Interdecadal Trichodesmium variability in cold North Atlantic waters

    Science.gov (United States)

    Rivero-Calle, Sara; Del Castillo, Carlos E.; Gnanadesikan, Anand; Dezfuli, Amin; Zaitchik, Benjamin; Johns, David G.

    2016-11-01

    Studies of the nitrogen cycle in the ocean generally assume that the distribution of the marine diazotroph, Trichodesmium, is restricted to warm, tropical, and subtropical oligotrophic waters. Here we show evidence that Trichodesmium are widely distributed in the North Atlantic. We report an approximately fivefold increase during the 1980s and 1990s in Trichodesmium presence near the British Isles with respect to the average over the last 50 years. A potential explanation is an increase in the Saharan dust source starting in the 1980s, coupled with changes in North Atlantic winds that opened a pathway for dust transport. Results from a coarse-resolution model in which winds vary but iron deposition is climatologically fixed suggest frequent nitrogen limitation in the region and reversals of the Portugal current, but it does not simulate the observed changes in Trichodesmium. Our results suggest that Trichodesmium may be capable of growth at temperatures below 20°C and challenge assumptions about their latitudinal distribution. Therefore, we need to reevaluate assumptions about the temperature limitations of Trichodesmium and the dinitrogen (N2) fixation capabilities of extratropical strains, which may have important implications for the global nitrogen budget.

  17. Effects of Atlantic warm pool variability over climate of South America tropical transition zone

    Science.gov (United States)

    Ricaurte Villota, Constanza; Romero-Rodríguez, Deisy; Andrés Ordoñez-Zuñiga, Silvio; Murcia-Riaño, Magnolia; Coca-Domínguez, Oswaldo

    2016-04-01

    Colombia is located in the northwestern corner of South America in a climatically complex region due to the influence processes modulators of climate both the Pacific and Atlantic region, becoming in a transition zone between phenomena of northern and southern hemisphere. Variations in the climatic conditions of this region, especially rainfall, have been attributed to the influence of the El Nino Southern Oscillation (ENSO), but little is known about the interaction within Atlantic Ocean and specifically Caribbean Sea with the environmental conditions of this region. In this work We studied the influence of the Atlantic Warm Pool (AWP) on the Colombian Caribbean (CC) climate using data of Sea Surface Temperature (SST) between 1900 - 2014 from ERSST V4, compared with in situ data SIMAC (National System for Coral Reef Monitoring in Colombia - INVEMAR), rainfall between 1953-2013 of meteorological stations located at main airports in the Colombian Caribbean zone, administered by IDEAM, and winds data between 2003 - 2014 from WindSat sensor. The parameters analyzed showed spatial differences throughout the study area. SST anomalies, representing the variability of the AWP, showed to be associated with Multidecadal Atlantic Oscillation (AMO) and with the index of sea surface temperature of the North-tropical Atlantic (NTA), the variations was on 3 to 5 years on the ENSO scale and of approximately 11 years possibly related to solar cycles. Rainfall anomalies in the central and northern CC respond to changes in SST, while in the south zone these are not fully engage and show a high relationship with the ENSO. Finally, the winds also respond to changes in SST and showed a signal approximately 90 days possibly related to the Madden-Julian Oscillation, whose intensity depends on the CC region being analyzed. The results confirm that region is a transition zone in which operate several forcing, the variability of climate conditions is difficult to attribute only one, as ENSO

  18. Health outcomes among HIV-positive Latinos initiating antiretroviral therapy in North America versus Central and South America

    Science.gov (United States)

    Cesar, Carina; Koethe, John R; Giganti, Mark J; Rebeiro, Peter; Althoff, Keri N; Napravnik, Sonia; Mayor, Angel; Grinsztejn, Beatriz; Wolff, Marcelo; Padgett, Denis; Sierra-Madero, Juan; Gotuzzo, Eduardo; Sterling, Timothy R; Willig, James; Levison, Julie; Kitahata, Mari; Rodriguez-Barradas, Maria C; Moore, Richard D; McGowan, Catherine; Shepherd, Bryan E; Cahn, Pedro

    2016-01-01

    Introduction Latinos living with HIV in the Americas share a common ethnic and cultural heritage. In North America, Latinos have a relatively high rate of new HIV infections but lower rates of engagement at all stages of the care continuum, whereas in Latin America antiretroviral therapy (ART) services continue to expand to meet treatment needs. In this analysis, we compare HIV treatment outcomes between Latinos receiving ART in North America versus Latin America. Methods HIV-positive adults initiating ART at Caribbean, Central and South America Network for HIV (CCASAnet) sites were compared to Latino patients (based on country of origin or ethnic identity) starting treatment at North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD) sites in the United States and Canada between 2000 and 2011. Cox proportional hazards models compared mortality, treatment interruption, antiretroviral regimen change, virologic failure and loss to follow-up between cohorts. Results The study included 8400 CCASAnet and 2786 NA-ACCORD patients initiating ART. CCASAnet patients were younger (median 35 vs. 37 years), more likely to be female (27% vs. 20%) and had lower nadir CD4 count (median 148 vs. 195 cells/µL, p<0.001 for all). In multivariable analyses, CCASAnet patients had a higher risk of mortality after ART initiation (adjusted hazard ratio (AHR) 1.61; 95% confidence interval (CI): 1.32 to 1.96), particularly during the first year, but a lower hazard of treatment interruption (AHR: 0.46; 95% CI: 0.42 to 0.50), change to second-line ART (AHR: 0.56; 95% CI: 0.51 to 0.62) and virologic failure (AHR: 0.52; 95% CI: 0.48 to 0.57). Conclusions HIV-positive Latinos initiating ART in Latin America have greater continuity of treatment but are at higher risk of death than Latinos in North America. Factors underlying these differences, such as HIV testing, linkage and access to care, warrant further investigation. PMID:26996992

  19. Effects of the North Atlantic Oscillation on Spanish catches of albacore, Thunnus alalunga, and yellowfin tuna, Thunnus albacares, in the North–east Atlantic Ocean

    Energy Technology Data Exchange (ETDEWEB)

    Rubio, C.J.; MacIas, D.; Camiñas, J.A.; Fernandez, I.L.; Baez, J.C.

    2016-07-01

    Tuna are highly migratory pelagic species (HMPS) with great importance in commercial fishing. Several authors have highlighted the effect of climatic oscillations such as the NAO (North Atlantic Oscillation) on HMPS. This paper analyzes the effects of the NAO on two HMPS: albacore, Thunnus alalunga, and yellowfin tuna, Thunnus albacares. Fishing data from the Spanish fleet operating in the North Atlantic area were obtained from the International Commission for the Conservation of Atlantic Tunas (ICCAT) database. The results show a positive correlation between the NAO index and the Catch per Unit Effort (CPUE) for both albacore and yellowfin tuna, depicting a potential effect on their capturability. (Author)

  20. First detection of bat white-nose syndrome in western North America

    Science.gov (United States)

    Lorch, Jeffrey M.; Palmer, Jonathan M.; Lindner, Daniel L.; Ballmann, Anne; George, Kyle; Griffin, Kathryn M.; Knowles, Susan N.; Huckabee, John R.; Haman, Katherine H.; Anderson, Christopher D.; Becker, Penny A.; Buchanan, Joseph B.; Foster, Jeffrey T.; Blehert, David

    2016-01-01

    White-nose syndrome (WNS) is an emerging fungal disease of bats caused by Pseudogymnoascus destructans. Since it was first detected near Albany, NY, in 2006, the fungus has spread across eastern North America, killing unprecedented numbers of hibernating bats. The devastating impacts of WNS on Nearctic bat species are attributed to the likely introduction of P. destructans from Eurasia to naive host populations in eastern North America. Since 2006, the disease has spread in a gradual wavelike pattern consistent with introduction of the pathogen at a single location. Here, we describe the first detection of P. destructans in western North America in a little brown bat (Myotis lucifugus) from near Seattle, WA, far from the previously recognized geographic distribution of the fungus. Whole-genome sequencing and phylogenetic analyses indicated that the isolate of P. destructans from Washington grouped with other isolates of a presumed clonal lineage from the eastern United States. Thus, the occurrence of P. destructans in Washington does not likely represent a novel introduction of the fungus from Eurasia, and the lack of intensive surveillance in the western United States makes it difficult to interpret whether the occurrence of P. destructans in the Pacific Northwest is disjunct from that in eastern North America. Although there is uncertainty surrounding the impacts of WNS in the Pacific Northwest, the presence of the pathogen in western North America could have major consequences for bat conservation.

  1. 77 FR 62535 - Hydro Aluminum North America, Inc., Midwest Region, Including On-Site Leased Workers From...

    Science.gov (United States)

    2012-10-15

    ... Aluminum North America, Inc., Midwest Region, Including On- Site Leased Workers From Employment Group, Aerotek, and Manpower, Kalamazoo, Michigan; Hydro Aluminum North America, Inc., Midwest Region, Including... Aluminum North America, Inc., Kalamazoo, Michigan. The subject worker group includes on-site leased workers...

  2. Geologic literature on North America, 1785-1918; Part I, Bibliography

    Science.gov (United States)

    Nickles, John M.

    1923-01-01

    The bibliography forming Part I of this compilation includes papers relating to the geology paleontology, petrology, and mineralogy of North America-specifically, the United States, the Dominion of Canada and Newfoundland, the Arctic regions north of the continent, Greenland, Mexico Central America, Panama, and the West Indies including Trinidad-and also the Hawaiian Islands. Geographic and descriptive writings and accounts of travels with incidental mention of geologic facts are not included. Textbooks published in America and work general in character by American authors are given but general papers by foreign writers are excluded unless they have appeared in American publications. Papers by American writers on the geology of other parts of the world are not listed.

  3. Climate drift of AMOC, North Atlantic salinity and arctic sea ice in CFSv2 decadal predictions

    Science.gov (United States)

    Huang, Bohua; Zhu, Jieshun; Marx, Lawrence; Wu, Xingren; Kumar, Arun; Hu, Zeng-Zhen; Balmaseda, Magdalena A.; Zhang, Shaoqing; Lu, Jian; Schneider, Edwin K.; Kinter, James L., III

    2015-01-01

    There are potential advantages to extending operational seasonal forecast models to predict decadal variability but major efforts are required to assess the model fidelity for this task. In this study, we examine the North Atlantic climate simulated by the NCEP Climate Forecast System, version 2 (CFSv2), using a set of ensemble decadal hindcasts and several 30-year simulations initialized from realistic ocean-atmosphere states. It is found that a substantial climate drift occurs in the first few years of the CFSv2 hindcasts, which represents a major systematic bias and may seriously affect the model's fidelity for decadal prediction. In particular, it is noted that a major reduction of the upper ocean salinity in the northern North Atlantic weakens the Atlantic meridional overturning circulation (AMOC) significantly. This freshening is likely caused by the excessive freshwater transport from the Arctic Ocean and weakened subtropical water transport by the North Atlantic Current. A potential source of the excessive freshwater is the quick melting of sea ice, which also causes unrealistically thin ice cover in the Arctic Ocean. Our sensitivity experiments with adjusted sea ice albedo parameters produce a sustainable ice cover with realistic thickness distribution. It also leads to a moderate increase of the AMOC strength. This study suggests that a realistic freshwater balance, including a proper sea ice feedback, is crucial for simulating the North Atlantic climate and its variability.

  4. Climate Prediction Center (CPC) Monthly North Atlantic Oscillation (NAO) teleconnection index

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly tabulated index of the North Atlantic Oscillation (NAO) teleconnection pattern. The data spans the period 1950 to present. The index is derived from a...

  5. PAGES-Powell North America 2k database

    Science.gov (United States)

    McKay, N.

    2014-12-01

    Syntheses of paleoclimate data in North America are essential for understanding long-term spatiotemporal variability in climate and for properly assessing risk on decadal and longer timescales. Existing reconstructions of the past 2,000 years rely almost exclusively on tree-ring records, which can underestimate low-frequency variability and rarely extend beyond the last millennium. Meanwhile, many records from the full spectrum of paleoclimate archives are available and hold the potential of enhancing our understanding of past climate across North America over the past 2000 years. The second phase of the Past Global Changes (PAGES) North America 2k project began in 2014, with a primary goal of assembling these disparate paleoclimate records into a unified database. This effort is currently supported by the USGS Powell Center together with PAGES. Its success requires grassroots support from the community of researchers developing and interpreting paleoclimatic evidence relevant to the past 2000 years. Most likely, fewer than half of the published records appropriate for this database are publicly archived, and far fewer include the data needed to quantify geochronologic uncertainty, or to concisely describe how best to interpret the data in context of a large-scale paleoclimatic synthesis. The current version of the database includes records that (1) have been published in a peer-reviewed journal (including evidence of the record's relationship to climate), (2) cover a substantial portion of the past 2000 yr (>300 yr for annual records, >500 yr for lower frequency records) at relatively high resolution (<50 yr/observation), and (3) have reasonably small and quantifiable age uncertainty. Presently, the database includes records from boreholes, ice cores, lake and marine sediments, speleothems, and tree rings. This poster presentation will display the site locations and basic metadata of the records currently in the database. We invite anyone with interest in

  6. South Atlantic Bight Habitat Mapping on NOAA Ship Nancy Foster in North Atlantic Ocean between 20070626 and 20070702

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This expedition on the NOAA Ship Nancy Foster used the recently-developed National Undersea Research Center for the North Atlantic and Great Lakes (NURC-NAGL) ROV...

  7. Status of RNB facilities in North America

    CERN Document Server

    Nolen, J A

    1998-01-01

    This paper presents the status of accelerator facilities in North America that are involved in research using radioactive nuclear beams (RNB), including existing and operating facilities, ones currently under construction or undergoing major upgrades, and ones being planned or proposed for the future. Existing RNB facilities are located at TRIUMF (TISOL) in Vancouver, B.C., the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory, the Argonne Tandem Linear Accelerator System (ATLAS) at Argonne National Laboratory, the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University, the Nuclear Structure Laboratory at the University of Notre Dame, the 88" Cyclotron at Lawrence Berkeley National Laboratory, and the Cyclotron Institute at Texas A&M University. Currently, there are two major RNB facility upgrades in progress in North America, one at TRIUMF, the ISAC project, and one at NSCL, the Intensity Upgrade project. For the future, the U.S. Nuclear Science A...

  8. The first reported ceratopsid dinosaur from eastern North America (Owl Creek Formation, Upper Cretaceous, Mississippi, USA).

    Science.gov (United States)

    Farke, Andrew A; Phillips, George E

    2017-01-01

    Ceratopsids ("horned dinosaurs") are known from western North America and Asia, a distribution reflecting an inferred subaerial link between the two landmasses during the Late Cretaceous. However, this clade was previously unknown from eastern North America, presumably due to limited outcrop of the appropriate age and depositional environment as well as the separation of eastern and western North America by the Western Interior Seaway during much of the Late Cretaceous. A dentary tooth from the Owl Creek Formation (late Maastrichtian) of Union County, Mississippi, represents the first reported occurrence of Ceratopsidae from eastern North America. This tooth shows a combination of features typical of Ceratopsidae, including a double root and a prominent, blade-like carina. Based on the age of the fossil, we hypothesize that it is consistent with a dispersal of ceratopsids into eastern North America during the very latest Cretaceous, presumably after the two halves of North America were reunited following the retreat of the Western Interior Seaway.

  9. The first reported ceratopsid dinosaur from eastern North America (Owl Creek Formation, Upper Cretaceous, Mississippi, USA

    Directory of Open Access Journals (Sweden)

    Andrew A. Farke

    2017-05-01

    Full Text Available Ceratopsids (“horned dinosaurs” are known from western North America and Asia, a distribution reflecting an inferred subaerial link between the two landmasses during the Late Cretaceous. However, this clade was previously unknown from eastern North America, presumably due to limited outcrop of the appropriate age and depositional environment as well as the separation of eastern and western North America by the Western Interior Seaway during much of the Late Cretaceous. A dentary tooth from the Owl Creek Formation (late Maastrichtian of Union County, Mississippi, represents the first reported occurrence of Ceratopsidae from eastern North America. This tooth shows a combination of features typical of Ceratopsidae, including a double root and a prominent, blade-like carina. Based on the age of the fossil, we hypothesize that it is consistent with a dispersal of ceratopsids into eastern North America during the very latest Cretaceous, presumably after the two halves of North America were reunited following the retreat of the Western Interior Seaway.

  10. The Atmospheric Response to a Future Warming Deficit in North Atlantic SSTs

    Science.gov (United States)

    Gervais, M.; Shaman, J. L.; Kushnir, Y.

    2017-12-01

    As SSTs increase globally over the 21st century, global climate models project a significant deficit in warming within the subpolar gyre of the North Atlantic Ocean. This study investigates the impact of this warming deficit on atmosphere circulation. A series of large ensemble experiments are conducted using the Community Atmosphere Model 5 forced with specified sea ice and SSTs for the early (2010-2019), mid (2050-2059), and late (2090-2099) 21stcentury. SST and sea ice fields from the Community Earth System Model Large Ensemble experiment are used as boundary conditions for the control simulations. Experiments with either a filled or deepened warming hole are conducted by adding a SST perturbation field to these time-varying SST boundary conditions. Results from these experiments demonstrate that the warming hole has significant local and remote impacts on the atmosphere. Filling (deepening) the warming hole results in a local increase (decrease) in turbulent heat fluxes relative to the control run and consequentially an increase (decrease) in temperature in the overlying lower troposphere that spreads over Europe. There are significant impacts on the location and strength of both the North Atlantic and North Pacific jets as well as on the North Atlantic Oscillation. These impacts of the warming hole on both the mean state and variability of the atmosphere have important implications for sensible weather in the Northern Hemisphere and in particular over Europe.

  11. An atypical biotype I Actinobacillus pleuropneumoniae serotype 13 is present in North America

    DEFF Research Database (Denmark)

    Perry, Malcolm B.; Angen, Øystein; MacLean, Leann L.

    2012-01-01

    Atypical Actinobacillus pleuropneumoniae serotype 13 strains present in North America are described here for the first time. Different from serotype 13 strains described in Europe, North America strains are biotype I and antigenically related to both, serotypes 13 and 10. Chemical and structural...

  12. Initializing decadal climate predictions over the North Atlantic region

    Science.gov (United States)

    Matei, Daniela Mihaela; Pohlmann, Holger; Jungclaus, Johann; Müller, Wolfgang; Haak, Helmuth; Marotzke, Jochem

    2010-05-01

    Decadal climate prediction aims to predict the internally-generated decadal climate variability in addition to externally-forced climate change signal. In order to achieve this it is necessary to start the predictions from the current climate state. In this study we investigate the forecast skill of the North Atlantic decadal climate predictions using two different ocean initialization strategies. First we apply an assimilation of ocean synthesis data provided by the GECCO project (Köhl and Stammer, 2008) as initial conditions for the coupled model ECHAM5/MPI-OM. Hindcast experiments are then performed over the period 1952-2001. An alternative approach is one in which the subsurface ocean temperature and salinity are diagnosed from an ensemble of ocean model runs forced by the NCEP-NCAR atmospheric reanalyzes for the period 1948-2007, then nudge into the coupled model to produce initial conditions for the hindcast experiments. An anomaly coupling scheme is used in both approaches to avoid the hindcast drift and the associated initial shock. Differences between the two assimilation approaches are discussed by comparing them with the observational data in key regions and processes. We asses the skill of the initialized decadal hindcast experiments against the prediction skill of the non-initialized hindcasts simulation. We obtain an overview of the regions with the highest predictability from the regional distribution of the anomaly correlation coefficients and RMSE for the SAT. For the first year the hindcast skill is increased over almost all ocean regions in the NCEP-forced approach. This increase in the hindcast skill for the 1 year lead time is somewhat reduced in the GECCO approach. At lead time 5yr and 10yr, the skill enhancement is still found over the North Atlantic and North Pacific regions. We also consider the potential predictability of the Atlantic Meridional Overturning Circulation (AMOC) and Nordic Seas Overflow by comparing the predicted values to

  13. A Reassessment of the Integrated Impact of Tropical Cyclones on Surface Chlorophyll in the Western Subtropical North Atlantic

    Energy Technology Data Exchange (ETDEWEB)

    Foltz, Gregory R.; Balaguru, Karthik; Leung, Lai-Yung R.

    2015-02-28

    The impact of tropical cyclones on surface chlorophyll concentration is assessed in the western subtropical North Atlantic Ocean during 1998–2011. Previous studies in this area focused on individual cyclones and gave mixed results regarding the importance of tropical cyclone-induced mixing for changes in surface chlorophyll. Using a more integrated and comprehensive approach that includes quantification of cyclone-induced changes in mixed layer depth, here it is shown that accumulated cyclone energy explains 22% of the interannual variability in seasonally-averaged (June–November) chlorophyll concentration in the western subtropical North Atlantic, after removing the influence of the North Atlantic Oscillation (NAO). The variance explained by tropical cyclones is thus about 70% of that explained by the NAO, which has well-known impacts in this region. It is therefore likely that tropical cyclones contribute significantly to interannual variations of primary productivity in the western subtropical North Atlantic during the hurricane season.

  14. The role of local sea surface temperature pattern changes in shaping climate change in the North Atlantic sector

    Science.gov (United States)

    Hand, Ralf; Keenlyside, Noel S.; Omrani, Nour-Eddine; Bader, Jürgen; Greatbatch, Richard J.

    2018-03-01

    Beside its global effects, climate change is manifested in many regionally pronounced features mainly resulting from changes in the oceanic and atmospheric circulation. Here we investigate the influence of the North Atlantic SST on shaping the winter-time response to global warming. Our results are based on a long-term climate projection with the Max Planck Institute Earth System Model (MPI-ESM) to investigate the influence of North Atlantic sea surface temperature pattern changes on shaping the atmospheric climate change signal. In sensitivity experiments with the model's atmospheric component we decompose the response into components controlled by the local SST structure and components controlled by global/remote changes. MPI-ESM simulates a global warming response in SST similar to other climate models: there is a warming minimum—or "warming hole"—in the subpolar North Atlantic, and the sharp SST gradients associated with the Gulf Stream and the North Atlantic Current shift northward by a few a degrees. Over the warming hole, global warming causes a relatively weak increase in rainfall. Beyond this, our experiments show more localized effects, likely resulting from future SST gradient changes in the North Atlantic. This includes a significant precipitation decrease to the south of the Gulf Stream despite increased underlying SSTs. Since this region is characterised by a strong band of precipitation in the current climate, this is contrary to the usual case that wet regions become wetter and dry regions become drier in a warmer climate. A moisture budget analysis identifies a complex interplay of various processes in the region of modified SST gradients: reduced surface winds cause a decrease in evaporation; and thermodynamic, modified atmospheric eddy transports, and coastal processes cause a change in the moisture convergence. The changes in the the North Atlantic storm track are mainly controlled by the non-regional changes in the forcing. The impact of

  15. Holocene climate and fjord glaciations in Northeast Greenland: implications for IRD deposition in the North Atlantic

    DEFF Research Database (Denmark)

    Reeh, Niels

    2004-01-01

    been released by intensive sub-glacial melting during the long stay of the ice-islands in coastal waters. The Holocene glacial geological record from Northeast Greenland is compared to the record of ice rafted debris (IRD) from North Atlantic deep-sea sediment cores. The comparison shows that transport...... by icebergs in the form of basal debris is unlikely to be the dominant transport mechanism of IRD to deposition sites in the North Atlantic during the Holocene. The ice rafted debris is more likely to be carried at the surface of sea- (or glacier) ice. This supports the result of previous studies by other...... workers that changes of atmospheric and ocean-surface circulation and temperature are the likely causes of Holocene cycles in IRD concentration in North Atlantic deep-sea sediments....

  16. Causes of decadal climate variability over the North Pacific and North America

    International Nuclear Information System (INIS)

    Latif, M.; Barnett, T.P.

    1994-01-01

    The cause of decadal climate variability over the North Pacific and North America is investigated by analyzing data from a multi-decadal integration with a state of the art coupled ocean-atmosphere model and observations. About one third of the low-frequency climate variability in the region of interest can be attributed to a cycle involving unstable air-sea interactions between the subtropical gyre circulation in the North Pacific and the Aleutian low pressure system. The existence of this cycle provides a basis for long-range climate forecasting over the western United States at decadal time scales. (orig.)

  17. Geologic and operational summary, COST No. 1 well, Georges Bank area, North Atlantic OCS

    Science.gov (United States)

    Amato, Roger V.; Bebout, John W.

    1980-01-01

    The first Continental Offshore Stratigraphic Test (COST) well on the U.S. North Atlantic Outer Continental Shelf (OCS) was drilled by Ocean Production Company between April 6 and July 26, 1976, and designated the COST No. G-l. Geological and engineering data obtained from this deep well in the Georges Bank Basin were used by the 31 participating companies and the U.S. Geological Survey (USGS) for evaluating the petroleum potential and possible drilling problems in the U.S. North Atlantic OCS area in preparation for Lease Sale 42 held on December 18, 1979.

  18. Sinking of Dense North Atlantic Waters in a Global Ocean Model : Location and Controls

    NARCIS (Netherlands)

    Katsman, C.A.; Drijfhout, SS; Dijkstra, H. A.; Spall, M. A.

    2018-01-01

    We investigate the characteristics of the sinking of dense waters in the North Atlantic Ocean that constitute the downwelling limb of the Atlantic Meridional Overturning Circulation (AMOC) as simulated by two global ocean models: an eddy-permitting model at 1/4° resolution and its coarser 1°

  19. Forest productivity in southwestern Europe is controlled by coupled North Atlantic and Atlantic Multidecadal Oscillations.

    Science.gov (United States)

    Madrigal-González, Jaime; Ballesteros-Cánovas, Juan A; Herrero, Asier; Ruiz-Benito, Paloma; Stoffel, Markus; Lucas-Borja, Manuel E; Andivia, Enrique; Sancho-García, Cesar; Zavala, Miguel A

    2017-12-20

    The North Atlantic Oscillation (NAO) depicts annual and decadal oscillatory modes of variability responsible for dry spells over the European continent. The NAO therefore holds a great potential to evaluate the role, as carbon sinks, of water-limited forests under climate change. However, uncertainties related to inconsistent responses of long-term forest productivity to NAO have so far hampered firm conclusions on its impacts. We hypothesize that, in part, such inconsistencies might have their origin in periodical sea surface temperature anomalies in the Atlantic Ocean (i.e., Atlantic Multidecadal Oscillation, AMO). Here we show strong empirical evidence in support of this hypothesis using 120 years of periodical inventory data from Iberian pine forests. Our results point to AMO + NAO + and AMO - NAO - phases as being critical for forest productivity, likely due to decreased winter water balance and abnormally low winter temperatures, respectively. Our findings could be essential for the evaluation of ecosystem functioning vulnerabilities associated with increased climatic anomalies under unprecedented warming conditions in the Mediterranean.

  20. LNG : its potential impact on North American markets

    International Nuclear Information System (INIS)

    Schlesinger, B.

    2003-01-01

    Liquefied natural gas (LNG) is expected to play a greater role in North American gas supplies and markets due to the decrease in conventional natural gas production in North America accompanied by an increase in demand for energy. It is expected that the overall share of the LNG gas market will rise from about 1.4 per cent in 2002 to more than 5 per cent by 2020, and potentially up to 15 per cent by that year. The construction of at least 15 new LNG receiving terminals has been proposed for location in the U.S., Canada, and Mexico. In addition, El Paso has proposed a novel offshore LNG receiving concept involving offshore gas pipelines and on-board-ship regasification. As trading of LNG increases in the Atlantic, markets in eastern United States and Canada will benefit from improved gas supplies, but pricing patterns are expected to change. Basis differentials along the Atlantic coastline will probably diminish, potentially reducing the value of Sable Island gas and the pipeline system that runs north to south along the eastern coast of North America. It was noted that Middle Eastern suppliers of LNG will play an important potential role in North American markets. 19 figs

  1. The Influence of the North Atlantic Oscillation on Tropospheric Distributions of Ozone and Carbon Monoxide.

    Science.gov (United States)

    Knowland, K. E.; Doherty, R. M.; Hodges, K.

    2015-12-01

    The influence of the North Atlantic Oscillation (NAO) on the tropospheric distributions of ozone (O3) and carbon monoxide (CO) has been quantified. The Monitoring Atmospheric Composition and Climate (MACC) Reanalysis, a combined meteorology and composition dataset for the period 2003-2012 (Innes et al., 2013), is used to investigate the composition of the troposphere and lower stratosphere in relation to the location of the storm track as well as other meteorological parameters over the North Atlantic associated with the different NAO phases. Cyclone tracks in the MACC Reanalysis compare well to the cyclone tracks in the widely-used ERA-Interim Reanalysis for the same 10-year period (cyclone tracking performed using the tracking algorithm of Hodges (1995, 1999)), as both are based on the European Centre for Medium-Range Weather Forecasts' (ECMWF) Integrated Forecast System (IFS). A seasonal analysis is performed whereby the MACC reanalysis meteorological fields, O3 and CO mixing ratios are weighted by the monthly NAO index values. The location of the main storm track, which tilts towards high latitudes (toward the Arctic) during positive NAO phases to a more zonal location in the mid-latitudes (toward Europe) during negative NAO phases, impacts the location of both horizontal and vertical transport across the North Atlantic and into the Arctic. During positive NAO seasons, the persistence of cyclones over the North Atlantic coupled with a stronger Azores High promotes strong horizontal transport across the North Atlantic throughout the troposphere. In all seasons, significantly more intense cyclones occur at higher latitudes (north of ~50°C) during the positive phase of the NAO and in the southern mid-latitudes during the negative NAO phase. This impacts the location of stratospheric intrusions within the descending dry airstream behind the associated cold front of the extratropical cyclone and the venting of low-level pollution up into the free troposphere within

  2. North America: Chapter 5

    Science.gov (United States)

    Schwartz, Mark D.; Beaubien, Elisabeth G.; Crimmins, Theresa M.; Weltzin, Jake F.; Edited by Schwartz, Mark D.

    2013-01-01

    Plant phenological observations and networks in North America have been largely local and regional in extent until recent decades. In the USA, cloned plant monitoring networks were the exception to this pattern, with data collection spanning the late 1950s until approximately the early 1990s. Animal observation networks, especially for birds have been more extensive. The USA National Phenology Network (USA-NPN), established in the mid-2000s is a recent effort to operate a comprehensive national-scale network in the United States. In Canada, PlantWatch, as part of Nature Watch, is the current national-scale plant phenology program.

  3. North America pipeline map

    International Nuclear Information System (INIS)

    Anon.

    2005-01-01

    This map presents details of pipelines currently in place throughout North America. Fifty-nine natural gas pipelines are presented, as well as 16 oil pipelines. The map also identifies six proposed natural gas pipelines. Major cities, roads and highways are included as well as state and provincial boundaries. The National Petroleum Reserve is identified, as well as the Arctic National Wildlife Refuge. The following companies placed advertisements on the map with details of the services they provide relating to pipeline management and construction: Ferus Gas Industries Trust; Proline; SulfaTreat Direct Oxidation; and TransGas. 1 map

  4. The medicinal use of chocolate in early North America.

    Science.gov (United States)

    Pucciarelli, Deanna L; Grivetti, Louis E

    2008-10-01

    The medicinal use of chocolate has a long history in North America dating back to the 16th century. From Mesoamerican Codices and European Treatises scholars have determined that for hundreds of years the beverage called chocolate was administered to the sick and prescribed homeopathically to prevent illness. Yet, little scholarship exists that focuses on medicinal chocolate usage in early North America (18th-19th century). This paper examines medical practices during this era and associated medicinal norms with special attention given to chocolate/cocoa usage. Given the current scientific attention on the relationship between dark chocolate consumption and heart disease attenuation it is timely to investigate and chronicle America's medical forebears' understanding of, and practices related to, the medicinal use of chocolate. Indeed, there is a significant amount of literature to suggest that chocolate was used for wellness and to treat illness.

  5. Radium 226 in the deep north-eastern Atlantic Ocean

    International Nuclear Information System (INIS)

    Rhein, M.

    1986-01-01

    With reference to the distribution of radium-226 in the western equatorial and north-eastern deep Atlantic Ocean it was possible to establish structures in the correlations of radium-226 to its chemical homologue Ba and dissolved SiO 2 . An 11-box model of the deep Atlantic Ocean was used to obtain information on the size of the radium-226 and Ba sources. The soil source derives mainly from the dissolution of barite. For the first time, an evaluation of the radium-226 flow resulting from the dissolution of particulate matter is presented. The box model and the radium-226 concentrations measured put down the value as 23-46·10 -21 mol/m 2 s. (DG) [de

  6. Overturn of the Oceasn Flow in the North Atlantic as a Trigger of Inertia Motion to Form a Meridional Ocean Circulation

    Science.gov (United States)

    Nakamura, Shigehisa

    2010-05-01

    This work is an introduction of a meridional ocean circulation. As for the zonal motions,there have been many contributions. Recent oceanographic works noticed an overturn of the ocean current in the North Atlantic. The author notices this overturn is a trigger to generate a meridional ocean circulation to have a track through the deep Atlantic, the deep circum-polar current, the deep branch flow to the Pacific between the Australian and the South America. The east part of the branch flow relates to the upwelling off Peru, and the west part relates to form a deep water in the Northwest Pacific. THe overturn of the North Atlantic suggests an outflow of the deep water and a storage of the old aged deep water in the Northwest Pacific. The storage water increase in the Northwest Pacific shoould be a trigger of the swelling up of the sea level mid Pacific to affect to the ocean front variations between the coastal waters and the ocean water. In order to keep a hydrodynamic balance on the earth, an increase of the deep water in the Pacific should flow through the Bering Sea and the Arctic Sea to get to the North Atlantic. It should be noted that a budget of the ocean water flow must be hold the condition of the water masses concservation on the earth surface. This inertia motion is maintained once induced after any natural effect or some man-made influences. At this stage, the author has to notice that there has been developed a meridional inertia path of the air particle as well as the ocean water parcel, nevertheless nobody has had pointed out this inertiamotion with a meridional path in the ocean. Air-sea interaction must be one of the main factors for driving the ocean water though the inertia motion in the global scale is more energetic. To the details, the scientists should pursue what geophysical dynamics must be developed in the future.

  7. Astronomically paced middle Eocene deepwater circulation in the western North Atlantic

    Science.gov (United States)

    Vahlenkamp, Maximilian; Niezgodzki, Igor; De Vleeschouwer, David; Bickert, Torsten; Harper, Dustin; Lohmann, Gerrit; Pälike, Heiko; Zachos, James C.

    2017-04-01

    The role of the Atlantic Meridional Overturning Circulation (AMOC) as a key player for abrupt climatic changes (e.g. Heinrich Stadials) during the Pleistocene is relatively well constrained. However, the timing of the onset of a „modern" North Atlantic Deepwater (NADW) formation are still debated: Recent estimates range from the middle Miocene to the Early Eocene [Davies et al., 2001, Stoker et al., 2005, Hohbein et al., 2012] and are mainly based on the seismic interpretation contourite drifts. Another understudied aspect of the AMOC is its behavior during climatic variations on orbital time scales and under different climatic boundary conditions (icehouse vs hothouse). IODP Expedition 342 drilled carbonate-rich sequences from sediment drifts offshore Newfoundland that cover the middle Eocene with high sedimentation rates ( 3 cm/ kyr). We present a 2 Myr long stable carbon and oxygen isotope record of benthic foraminifera nuttalides truempyi spanning magnetochron C20r in unprecedented resolution (Petroleum Geology, v. 22, no. 9, p. 977-1005. Hohbein, M. W., Sexton, P. F., and Cartwright, J. A., 2012, Onset of North Atlantic Deep Water production coincident with inception of the Cenozoic global cooling trend: Geology, v. 40, no. 3, p. 255-258.

  8. 75 FR 20390 - Robert Bosch LLC, Including On-Site Leased Workers From Bosch Management Services North America...

    Science.gov (United States)

    2010-04-19

    ...-site leased workers of Bosch Management Services North America, South Haven Community Hospital... leased workers of Bosch Management Services North America, South Haven Community Hospital, Huffmaster Inc..., Including On-Site Leased Workers From Bosch Management Services North America, South Haven Community...

  9. First report of the post-fire morel Morchella exuberans in eastern North America.

    Science.gov (United States)

    Miller, Andrew N; Raudabaugh, Daniel B; Iturriaga, Teresa; Matheny, P Brandon; Petersen, Ronald H; Hughes, Karen W; Gube, Matthias; Powers, Rob A; James, Timothy Y; O'Donnell, Kerry

    2017-01-01

    Reports of true morels (Morchella) fruiting on conifer burn sites are common in western North America where five different fire-adapted species of black morels (Elata Clade) have been documented based on multilocus phylogenetic analyses. Fruiting of post-fire morels in eastern North America, by comparison, are rare and limited to a report from Minnesota in 1977 and eastern Ontario in 1991. Here, nuc rDNA internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) sequences were used to identify the post-fire morel that fruited in great abundance the year following the 2012 Duck Lake Fire in the Upper Peninsula of Michigan and after the 2016 large-scale fire in the Great Smoky Mountains National Park in Tennessee as M. exuberans. A preliminary phylogenetic analysis suggests that the collections from eastern North America may be more closely related to those from Europe than from western North America, Europe, and China.

  10. Are Calanus spp. shifting poleward in the North Atlantic? A habitat modelling approach

    KAUST Repository

    Chust, Guillem

    2013-09-16

    In the last decade, the analysis based on Continuous Plankton Recorder survey in the eastern North Atlantic Ocean detected one of the most striking examples of marine poleward migration related to sea warming. The main objective of this study is to verify the poleward shift of zooplankton species (Calanus finmarchicus, C. glacialis, C. helgolandicus, C. hyperboreus) for which distributional changes have been recorded in the North Atlantic Ocean and to assess how much of this shift was triggered by sea warming, using Generalized Additive Models. To this end, the population gravity centre of observed data was compared with that of a series of simulation experiments: (i) a model using only climate factors (i.e. niche-based model) to simulate species habitat suitability, (ii) a model using only temporal and spatial terms to reconstruct the population distribution, and (iii) a model using both factors combined, using a subset of observations as independent dataset for validation. Our findings show that only C. finmarchicus had a consistent poleward shift, triggered by sea warming, estimated in 8.1 km per decade in the North Atlantic (16.5 per decade for the northeast), which is substantially lower than previous works at the assemblage level and restricted to the Northeast Atlantic. On the contrary, C. helgolandicus is expanding in all directions, although its northern distribution limit in the North Sea has shifted northward. Calanus glacialis and C. hyperboreus, which have the geographic centres of populations mainly in the NW Atlantic, showed a slight southward shift, probably responding to cool water penetrating southward in the Labrador Current. Our approach, supported by high model accuracy, shows its power in detecting species latitudinal shifts and identifying its causes, since the trend of occurrence observed data is influenced by the sampling frequency, which has progressively concentrated to lower latitudes with time. © 2013 © 2013 International Council for

  11. Cenozoic uplift and subsidence in the North Atlantic region

    DEFF Research Database (Denmark)

    Anell, Ingrid Anna Margareta; Thybo, Hans; Artemieva, Irina

    2009-01-01

    and the surrounding areas. (2) A regional increase in subsidence in the offshore marginal areas of Norway, the northern North Sea, the northern British Isles and west Greenland took place in the Eocene (ca 57-35 Ma). (3) The Oligocene and Miocene (35-5 Ma) were characterized by regional tectonic quiescence, with only...... localised uplift, probably related to changes in plate dynamics. (4) The second major phase of regional uplift that affected all marginal areas of the North Atlantic occurred in the Plio-Pleistocene (5-0 Ma). Its amplitude was enhanced by erosion-driven glacio-isostatic compensation. Despite inconclusive...

  12. Observed and Modeled Pathways of the Iceland Scotland Overflow Water in the eastern North Atlantic

    Science.gov (United States)

    Zou, Sijia; Lozier, Susan; Zenk, Walter; Bower, Amy; Johns, William

    2017-04-01

    The Iceland Scotland Overflow Water (ISOW), one of the major components of the lower limb of the Atlantic Meridional Overturning Circulation (AMOC), is formed in the Nordic Seas and enters the eastern North Atlantic subpolar gyre via the Iceland-Scotland sill. After entraining the ambient waters, the relatively homogeneous ISOW spreads southward into the North Atlantic. An understanding of the distribution and variability of the spreading pathways of the ISOW is fundamental to our understanding of AMOC structure and variability. Three major ISOW pathways have been identified in the eastern North Atlantic by previous studies: 1) across the Reykjanes Ridge via deep gaps, 2) through the Charlie Gibbs Fracture Zone, and 3) southward along the eastern flank of the Mid Atlantic Ridge (MAR). However, most of these studies were conducted using an Eulerian frame with limited observations, especially for the third pathway along the eastern flank of the MAR. In this work, we give a comprehensive description of ISOW pathways in the Eulerian and Lagrangian frames, quantify the relative importance of each pathway and examine the temporal variability of these pathways. Our study distinguishes itself from past studies by using both Eulerian (current meter data) and Lagrangian (eddy-resolving RAFOS float data) observations in combination with modeling output (1/12° FLAME) to describe ISOW spreading pathways and their variability.

  13. Arctic-midlatitude weather linkages in North America

    Science.gov (United States)

    Overland, James E.; Wang, Muyin

    2018-06-01

    There is intense public interest in whether major Arctic changes can and will impact midlatitude weather such as cold air outbreaks on the central and east side of continents. Although there is progress in linkage research for eastern Asia, a clear gap is conformation for North America. We show two stationary temperature/geopotential height patterns where warmer Arctic temperatures have reinforced existing tropospheric jet stream wave amplitudes over North America: a Greenland/Baffin Block pattern during December 2010 and an Alaska Ridge pattern during December 2017. Even with continuing Arctic warming over the past decade, other recent eastern US winter months were less susceptible for an Arctic linkage: the jet stream was represented by either zonal flow, progressive weather systems, or unfavorable phasing of the long wave pattern. The present analysis lays the scientific controversy over the validity of linkages to the inherent intermittency of jet stream dynamics, which provides only an occasional bridge between Arctic thermodynamic forcing and extended midlatitude weather events.

  14. Rethinking Atlantic History

    Directory of Open Access Journals (Sweden)

    James Walvin

    2009-12-01

    Full Text Available [First paragraph] Shaping the Stuart World 1603-1714: The Atlantic Connection. Allan I. Macinnes & Arthur H. Williamson (eds.. Leiden: Brill Academic Publishers, 2006. xiv + 389 pp. (Cloth US$ 135.00 Slavery and the British Empire: From Africa to America. Kenneth Morgan. New York: Oxford University Press, 2007. x + 221 pp. (Paper US$ 32.00 Although an important debate continues about the concept itself, the use of “the Atlantic” has embedded itself in scholarly vernacular. The scholarly output directly spawned by an engagement with the concept continues apace. That ocean, and the peoples who lived and traded along its edges, and who finally moved across it, have provided an important geographical focus for some major reconsiderations of modern history. Prompted by the Macinnes/Williamson volume, I returned to my own undergraduate and graduate notes and essays from courses on Stuart Britain: the Atlantic was totally absent – not even present as a distant speck on our intellectual map. We studied, and debated, the formal histories of migrations to the Americas (i.e. European migrations but there was no mention of Africa or Africans. And no sense was conveyed that the European engagement with the Americas (in their totality – as opposed to North America was a two-way, mutual force: that the European world was influenced, indeed shaped in many critical regards, by the Americas: by the land, the products, the peoples, and by the markets of that hemisphere. At its most obvious in the ebb and flow of peoples, even that eluded the historians I encountered as a student. It was as if we were talking about a different cosmos; few moved beyond the conventions of European migrations westwards and little attention was paid to that most dominant of migrations – the enforced African migrations to the Americas.

  15. CHARACTERIZATION OF WESTERN NORTH ATLANTIC RIGHT WHALE SPRING FEEDING HABITAT

    Science.gov (United States)

    The Great South Channel region of the southwestern Gulf of Maine, between George's Bank and Cape Cod, is the primary spring feeding ground for the western North Atlantic population of the I northern right whale, E. glacialis .Since this whale is so endangered, it is critical to i...

  16. Paleoenvironmental Reconstruction of the North Atlantic Current Variations from MIS 3 to Holocene Based on Multiproxy Record from the North-East Scotland Continental Margin.

    Science.gov (United States)

    Ovsepyan, Y.; Tikhonova, A.; Novichkova, E.; Gupta, R. M.; Korsun, S.; Matul, A.

    2017-12-01

    In order to reconstruct the history of water mass interaction between the North Atlantic and the Nordic Seas since MIS 3 to the present, the sediment core from the North-East Scotland continental slope was investigated. The site of core AI-3521 (59°30.009 N, 7°20.062 E) from the 1051 m water depth is located beneath the pathway of the North Atlantic current which transports warm and saline Atlantic surface water to the Norwegian Sea. The age model of the sequence is based on stable isotope record of benthic Cassidulina neoteretis and planktic Neogloboquadrina pachyderma sin. and Globigerina bulloides. The Holocene interval of the upper 1.5 m is characterized by high sedimentation rates and the high biodiversity of microfauna. The distribution of ice rafted debris and CaCO3 content; benthic and planktic foraminiferal assemblages; oxygen, carbon and boron isotopes, Mg/Ca ratio were used to reconstruct the regional paleoceanographic conditions (bioproductivity, temperature, salinity) and to compare with the paleoclimatic events in the subpolar North Atlantic in the frame of the global environmental changes during the Late Pleistocene and Holocene. The research was supported by Russian Science Foundation projects 16-47-02009 and 14-50-00095.

  17. Historical North Atlantic Tropical Cyclone Tracks 1851-2005, Geographic NAD83, NOAA (2006) [atlantic_hurricane_tracks_1851_2005_NOAA_2006

    Data.gov (United States)

    Louisiana Geographic Information Center — This Historical North Atlantic Tropical Cyclone Tracks file contains the 6-hourly (0000, 0600, 1200, 1800 UTC) center locations and intensities for all subtropical...

  18. Bathymetric controls on Pliocene North Atlantic and Arctic sea surface temperature and deepwater production

    Science.gov (United States)

    Robinson, M.M.; Valdes, P.J.; Haywood, A.M.; Dowsett, H.J.; Hill, D.J.; Jones, S.M.

    2011-01-01

    The mid-Pliocene warm period (MPWP; ~. 3.3 to 3.0. Ma) is the most recent interval in Earth's history in which global temperatures reached and remained at levels similar to those projected for the near future. The distribution of global warmth, however, was different than today in that the high latitudes warmed more than the tropics. Multiple temperature proxies indicate significant sea surface warming in the North Atlantic and Arctic Oceans during the MPWP, but predictions from a fully coupled ocean-atmosphere model (HadCM3) have so far been unable to fully predict the large scale of sea surface warming in the high latitudes. If climate proxies accurately represent Pliocene conditions, and if no weakness exists in the physics of the model, then model boundary conditions may be in error. Here we alter a single boundary condition (bathymetry) to examine if Pliocene high latitude warming was aided by an increase in poleward heat transport due to changes in the subsidence of North Atlantic Ocean ridges. We find an increase in both Arctic sea surface temperature and deepwater production in model experiments that incorporate a deepened Greenland-Scotland Ridge. These results offer both a mechanism for the warming in the North Atlantic and Arctic Oceans indicated by numerous proxies and an explanation for the apparent disparity between proxy data and model simulations of Pliocene northern North Atlantic and Arctic Ocean conditions. Determining the causes of Pliocene warmth remains critical to fully understanding comparisons of the Pliocene warm period to possible future climate change scenarios. ?? 2011.

  19. Ecohydrological change and variability over western North America from the Last Glacial Maximum to the near term future: The known, the unknown and the known unknown

    Science.gov (United States)

    Seager, R.; Mankin, J. S.; Cook, B.; Scheff, J.; Smerdon, J. E.; Coats, S.; Williams, P.

    2017-12-01

    Hydroclimate variability and change in western North America from the last glacial to the near future is reviewed focusing on non-orbital-induced variations. The motivating factor is model projections of intensifying aridity in southwestern North America as a consequence of rising greenhouse gases. Future change will be considered in the context of changes in precipitation, evaporative demand and CO2 and from perspectives of surface hydroclimate and ecological response. Current earth system models project increasing aridity in terms of standard drought measures and declining soil moisture quite robustly as a consequence of declining precipitation (in the interior southwest) and rising evaporative demand (everywhere). However, the same models project rising net primary production, leaf area index and evapotranspiration as the effects on plants of increasing CO2 outweigh the effects of increased water stress. There are reasons to be cautious about the realism of this modeled response but it poses a future with a competition between ecosystems and humans (dependent on soil moisture and runoff) for available water. Looking back over the last millennium with the aid of near hemispheric tree ring drought reconstructions we show that the driving role the tropical Pacific and tropical North Atlantic Oceans have in orchestrating the sequence of western droughts and pluvials extends to the Medieval megadroughts. These famed severe and extended droughts, still visible in the landscape today, were most likely caused by internal atmosphere-ocean variability including frequent, but not anomalously recurrent, La Nina-conditions accompanied by persistent warm shifts in the tropical North Atlantic. Passing over early and mid-Holocene climates that were strongly influenced by orbitally-forcing, we turn to Last Glacial Maximum climates. According to lake records the LGM was moist across western North America while pollen records show a mix of wetter-looking and less lush ("drier

  20. North America-Greenland-Eurasian relative motions: implications for circum-arctic tectonic reconstructions

    Energy Technology Data Exchange (ETDEWEB)

    Rowley, D.B.; Lottes, A.L.; Ziegler, A.M.

    1985-02-01

    The Mesozoic-Cenozoic tectonic evolution of the Circum-Arctic region is based on constraints imposed by (1) relative motion histories of the three major plates (North America, Greenland, and Eurasia) and a number of smaller pieces, and (2) distribution and age of sutures, accretionary prisms, volcanic arcs, fold-thrust belts, stretched continental crust, strike-slip faults, and ocean floor. The authors conclude that: (1) North America and Eurasia remained relatively fixed to each other until the latest Cretaceous-Paleocene opening of the Labrador Sea-Baffin Bay and Greenland-Norwegian and Eurasian basins (earlier convergence between North America and Eurasia in the Bering Sea region shown on many reconstructions are artifacts of incorrect plate reconstructions); (2) the North Slope-Seward-Chukotka block has constituted an isthmus connection between North America and northeast Asia since at least the middle Paleozoic and did not rotate away from the Canadian Arctic; (3) the Canada basin opened behind a clockwise-rotating Alpha Cordillera-Mendeleyev ridge arc during the Early to middle Cretaceous and consumed older, Paleozoic(.) Makarov basin ocean floor (the Chukchi cap is a detached continental fragment derived from the Beaufort Sea; the North Slope Arctic margin is a left-lateral transform fault associated with the opening of the Canada basin); and (4) the Nares Strait fault has a net relative displacement of approximately 25 km, but actual motion between Greenland and northern Ellesmere was about 250 km of strongly transpressive motion that resulted in the Eurekan and Svalbardian orogenies.

  1. Encountered Wave Height Distributions for Ships in the North Atlantic

    DEFF Research Database (Denmark)

    Olsen, Anders Smærup; Schrøter, C.; Jensen, Jørgen Juncher

    2004-01-01

    About 20 000 observations of wave heights taken on board vessels sailing in the North Atlantic are presented. The data covers year 2002 and 2003 and stem from a variety of ship types. From the preliminary analysis of the data some conclusions are reached about the effect of weather routing whether...

  2. Book review: Bumble bees of North America

    Science.gov (United States)

    O'Dell, Samuel

    2015-01-01

    Bumblebee identification is generally considered straightforward, yet mistakes often are made due to the degree of similarity between the color patterns of different species. Bumble Bees of North America aims to improve the accuracy of identifications by both casual observers and professionals through the use of intuitive diagrams, descriptions, and the more technical dichotomous keys. In addition to providing the first complete field guide to North American bumblebees, the authors make efficient use of the reader’s attention by summarizing taxonomic history, favored food plants, and environmental issues concerning bumblebees.

  3. Remote Drying in the North Atlantic as a Common Response to Precessional Changes and CO2 Increase Over Land

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Patrick [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Atmospheric Sciences and Global Change Division; Kravitz, Ben [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Atmospheric Sciences and Global Change Division; Lu, Jian [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Atmospheric Sciences and Global Change Division; Leung, L. Ruby [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Atmospheric Sciences and Global Change Division

    2018-04-16

    Here we demonstrate that changes of the North Atlantic subtropical high (NASH) and its regional rainfall pattern during mid-Holocene precessional changes and idealized 4xCO2 increase can both be understood as a remote response to changes in the African and Indian monsoon systems. Despite different sources and patterns of radiative forcing (increase in CO2 concentration vs. changes in orbital parameters), we find that the pattern of energy, circulation, and rainfall responses in the Northern Hemisphere summer subtropics are very similar in the two forcing scenarios because both are dominated by the same land-sea heating contrast in response to the forcing. An increase in energy input over land drives a westward displacement of the coupled NASH-monsoon circulation, consistent with increased precipitation in the Afro-Asia region and decreased precipitation in the America-Atlantic region. Ultimately, this study underscores the importance of land heating in dictating remote drying through zonal shifts of the subtropical circulation.

  4. Refining the learning process in Newfoundland : E-learning innovation at North Atlantic

    Energy Technology Data Exchange (ETDEWEB)

    Murray, D.

    2001-11-01

    The Learning Technologies in the Workplace Awards were launched by the Conference Board of Canada in April 2001 with funding from Human Resources Development Canada's Office of Learning Technologies. This paper described the innovative and outstanding efforts made by the winner, North Atlantic. The North Atlantic refinery is located on an inlet on the Avalon Peninsula approximately 135 kilometres west of St. John's, Newfoundland. Each day, 105,000 barrels of oil are processed for export to 25 countries. In 1998, the company recognized that better training was required in the areas of improved safety, performance, and employee innovation and capacity. The isolation faced by the employees was a key driver behind the decision to implement the TRAQS training program in 1999 for e-learning developed by Illuminatus. This on-line training program also features testing through CHALLENGE, a software package compatible with TRAQS learning management system. Process emergency simulation exercises were developed by North Atlantic which are now being used externally. Job-specific technical information is delivered through the local area network (LAN). The keys to success were identified as being: innovative organizational culture; vision and action; executive management support, commitment to learning and employee development; positive work life balance; union cooperation; technology intensive workplace; linking learning with work process and performance management; and, tracking and certification.

  5. Links between North Atlantic atmospheric blocking and recent trends in European winter precipitation

    Science.gov (United States)

    Ummenhofer, Caroline; Seo, Hyodae; Kwon, Young-Oh; Joyce, Terrence

    2015-04-01

    European precipitation has sustained robust trends during wintertime (January - March) over recent decades. Central, western, and northern Europe have become wetter by an average 0.1-0.3% per annum for the period 1901-2010, while southern Europe, including the Iberian Peninsula, much of Italy and the Balkan States, has sustained drying of -0.2% per annum or more over the same period. The overall pattern is consistent across different observational precipitation products, while the magnitude of the precipitation trends varies amongst data sets. Using cluster analysis, which identifies recurrent states (or regimes) of European winter precipitation by grouping them according to an objective similarity criterion, changes in the frequency of dominant winter precipitation patterns over the past century are evaluated. Considerable multi-decadal variability exists in the frequency of dominant winter precipitation patterns: more recent decades are characterised by significantly fewer winters with anomalous wet conditions over southern, western, and central Europe. In contrast, winters with dry conditions in western and southern Europe, but above-average rainfall in western Scandinavia and the northern British Isles, have been more common recently. We evaluate the associated multi-decadal large-scale circulation changes across the broader extratropical North Atlantic region, which accompany the observed wintertime precipitation variability using the 20th Century reanalysis product. Some influence of the North Atlantic Oscillation (NAO) is apparent in modulating the frequency of dominant precipitation patterns. However, recent trends in the characteristics of atmospheric blocking across the North Atlantic sector indicate a change in the dominant blocking centres (near Greenland, the British Isles, and west of the Iberian Peninsula). Associated changes in sea level pressure, storm track position and strength, and oceanic heat fluxes across the North Atlantic region are also

  6. Climate and vegetation changes around the Atlantic Ocean resulting from changes in the meridional overturning circulation during deglaciation

    Science.gov (United States)

    Handiani, D.; Paul, A.; Dupont, L.

    2012-07-01

    The Bølling-Allerød (BA, starting ~ 14.5 ka BP) is one of the most pronounced abrupt warming periods recorded in ice and pollen proxies. The leading explanation of the cause of this warming is a sudden increase in the rate of deepwater formation in the North Atlantic Ocean and the resulting effect on the heat transport by the Atlantic Meridional Overturning Circulation (AMOC). In this study, we used the University of Victoria (UVic) Earth System-Climate Model (ESCM) to run simulations, in which a freshwater perturbation initiated a BA-like warming period. We found that under present climate conditions, the AMOC intensified when freshwater was added to the Southern Ocean. However, under Heinrich event 1 (HE1, ~ 16 ka BP) climate conditions, the AMOC only intensified when freshwater was extracted from the North Atlantic Ocean, possibly corresponding to an increase in evaporation or a decrease in precipitation in this region. The intensified AMOC led to a warming in the North Atlantic Ocean and a cooling in the South Atlantic Ocean, resembling the bipolar seesaw pattern typical of the last glacial period. In addition to the physical response, we also studied the simulated vegetation response around the Atlantic Ocean region. Corresponding with the bipolar seesaw hypothesis, the rainbelt associated with the Intertropical Convergence Zone (ITCZ) shifted northward and affected the vegetation pattern in the tropics. The most sensitive vegetation area was found in tropical Africa, where grass cover increased and tree cover decreased under dry climate conditions. An equal but opposite response to the collapse and recovery of the AMOC implied that the change in vegetation cover was transient and robust to an abrupt climate change such as during the BA period, which is also supported by paleovegetation data. The results are in agreement with paleovegetation records from Western tropical Africa, which also show a reduction in forest cover during this time period. Further

  7. Opportunities and uses of biochar on forest sites in North America [Chapter 15

    Science.gov (United States)

    Deborah S. Page-Dumroese; Mark D. Coleman; Sean C. Thomas

    2017-01-01

    Biochar may be useful for restoring or revitalizing degraded forest soils and help with carbon sequestration, nutrient leaching losses, and reducing greenhouse gas emissions. However, biochar is not currently widely used on forested lands across North America. This chapter provides an overview of several biochar experiments conducted in North America and discusses the...

  8. DNA from Pre-Clovis Human Coprolites in Oregon, North America

    DEFF Research Database (Denmark)

    Gilbert, M Thomas P; Jenkins, Dennis L; Götherstrom, Anders

    2008-01-01

    The timing of the first human migration into the Americas and its relation to the appearance of the Clovis technological complex in North America ca. 11-10.8 thousand radiocarbon years before present ((14)C ka B.P.) remains contentious. We establish that humans were present at Paisley 5 Mile Point...

  9. Two new species of Dendrobrachia Brook, 1889 (Cnidaria: Octocorallia: Dendrobrachiidae from the north-eastern Atlantic and western Mediterranean

    Directory of Open Access Journals (Sweden)

    Pablo J. López-González

    2010-08-01

    Full Text Available Examination of recent benthic material collected during several cruises in the Gulf of Cadiz (NE Atlantic and the Strait of Sicily (Mediterranean has allowed the taxonomic reassessment of some previously identified specimens belonging to the monogeneric gorgonian family Dendrobrachiidae Brook, 1889. Dendrobrachia fallax Brook, 1889 is the type species of the single genus in this family, and was originally described from Ascension Island (South Atlantic. Subsequently, other authors reported the presence of this species in Cape Verde Islands (north-eastern Atlantic and some Mediterranean localities (Alboran Sea and the Strait of Sicily. The study of the specimen from the Prince of Monaco collections in Cape Verde Islands, and recently collected material from the Gulf of Cadiz (north-eastern Atlantic and in the south of Malta (Mediterranean, materials previously considered as D. fallax, allow us to recognize two undescribed species in this genus. All previous records of D. fallax from the north-eastern Atlantic and Mediterranean should be considered incorrect. Opresko and Bayer (1991 added two additional species of Dendrobrachia. Two new species are described here and compared with their congeners.

  10. Electron beam curing of composites in North America

    International Nuclear Information System (INIS)

    Berejka, Anthony J.; Eberle, Cliff

    2002-01-01

    Electron beam curing of fiber-reinforced composites was explored over 30 years ago. Since then there have been developments in accelerator technology, in processes for handling materials presented to an accelerator, and in materials that can be used as matrix binders. In recent years in North America, Cooperative Research and Development Agreements (CRADAs) have been formed involving collaboration amongst materials suppliers, accelerator manufacturers and service providers, national laboratories, such as Oak Ridge National Laboratory, and interested potential users. The scope and status of these CRADAs are reviewed along with other recent developments in the electron beam curing of composites in North America. Innovative and proprietary materials technology has been developed and progress made toward implementing commercial practice. Significant market interest has developed in the military/aerospace industries that are finding the process and performance of electron beam cured composites to offer significant benefits

  11. Cross-continental patterns in the timing of southward Peregrine Falcon migration in North America

    NARCIS (Netherlands)

    Worcester, R.; Ydenberg, R.C.

    2008-01-01

    We analyzed the timing of southward migration of Peregrine Falcons (Falco peregrinus) across North America, based on passage data compiled by the Hawk Migration Association of North America, supplemented with two other similar datasets collected by individual observers at sites in western Canada.

  12. The link between eddy-driven jet variability and weather regimes in the North Atlantic-European sector

    Science.gov (United States)

    Madonna, E.; Li, C.; Grams, C. M.; Woollings, T.

    2017-12-01

    Understanding the variability of the North Atlantic eddy-driven jet is key to unravelling the dynamics, predictability and climate change response of extratropical weather in the region. This study aims to 1) reconcile two perspectives on wintertime variability in the North Atlantic-European sector and 2) clarify their link to atmospheric blocking. Two common views of wintertime variability in the North Atlantic are the zonal-mean framework comprising three preferred locations of the eddy-driven jet (southern, central, northern), and the weather regime framework comprising four classical North Atlantic-European regimes (Atlantic ridge AR, zonal ZO, European/Scandinavian blocking BL, Greenland anticyclone GA). We use a k-means clustering algorithm to characterize the two-dimensional variability of the eddy-driven jet stream, defined by the lower tropospheric zonal wind in the ERA-Interim reanalysis. The first three clusters capture the central jet and northern jet, along with a new mixed jet configuration; a fourth cluster is needed to recover the southern jet. The mixed cluster represents a split or strongly tilted jet, neither of which is well described in the zonal-mean framework, and has a persistence of about one week, similar to the other clusters. Connections between the preferred jet locations and weather regimes are corroborated - southern to GA, central to ZO, and northern to AR. In addition, the new mixed cluster is found to be linked to European/Scandinavian blocking, whose relation to the eddy-driven jet was previously unclear. The results highlight the necessity of bridging from weather to climate scales for a deeper understanding of atmospheric circulation variability.

  13. Projected hydrogen cost from methane reforming for North America 2015-2050

    International Nuclear Information System (INIS)

    Vanderveen, K.; Lutz, A.; Klebanoff, L.; Drennen, T.; Keller, J.; Drennen, T.; Kamery, W.

    2006-01-01

    The Hydrogen Futures Simulation Model (H 2 Sim) was used to project the cost for hydrogen at the point of sale to light duty vehicles for distributed, small-scale steam methane reforming. Projections cover the period from 2010-2050 in North America, and take into account assumptions about the quantity of recoverable natural gas remaining in North America. We conclude that there is a window for distributed reforming to play a positive role in supplying a H 2 fuel infrastructure, but this window is closing rapidly. The analysis assumes that production from natural gas reserves in North America will peak sometime before 2050 and demand will cause the price to rise after the peak of production in a manner consistent with Hotelling's model. We consider three scenarios for when the peak occurs, and evaluate the impact on the cost of hydrogen fuel produced via distributed small scale reforming in these three scenarios. (authors)

  14. Structural (Performance) class Potential for North America

    Science.gov (United States)

    Eric Jones; David E. Kretschmann; Kevin Cheung

    2014-01-01

    Structural class systems are species-independent product classification systems for structural timber. They are used throughout the world to reduce the number of species and grade choices that face the designer of wood construction projects. Structural class systems offer an opportunity to simplify timber specification in North America and to encourage more effective...

  15. Phylogeography and population dynamics of the white-sided dolphin (Lagenorhynchus acutus) in the North Atlantic

    KAUST Repository

    Banguera-Hinestroza, E.; Evans, P. G H; Mirimin, L.; Reid, R. J.; Mikkelsen, B.; Couperus, A. S.; Deaville, R.; Rogan, E.; Hoelzel, A. R.

    2014-01-01

    Highly mobile species in the marine environment may be expected to show little differentiation at the population level, but this is often not the case. Instead cryptic population structure is common, and effective conservation will require an understanding of how these patterns evolve. Here we present an assessment from both sides of the North Atlantic of differentiation among populations of a dolphin species that inhabits mainly pelagic waters, the Atlantic white-sided dolphin. We compare eleven putative populations in the western and eastern North Atlantic at mtDNA and microsatellite DNA loci and find reduced nucleotide diversity and signals for historical bottlenecks and post-bottleneck expansions in all regions. We calculate expansion times to have occurred during the early Holocene, following the last glacial maximum (LGM). We find evidence for connectivity among populations from either side of the North Atlantic, and differentiation between putative populations in the far northeast compared with all other areas sampled. Some data suggest the possibility of separate refugia during the LGM explaining this pattern, although ongoing ecological processes may also be a factor. We discuss the implications for developing effective programs of conservation and management in the context of ongoing anthropogenic impact. © 2014 Springer Science+Business Media Dordrecht.

  16. Phylogeography and population dynamics of the white-sided dolphin (Lagenorhynchus acutus) in the North Atlantic

    KAUST Repository

    Banguera-Hinestroza, E.

    2014-02-27

    Highly mobile species in the marine environment may be expected to show little differentiation at the population level, but this is often not the case. Instead cryptic population structure is common, and effective conservation will require an understanding of how these patterns evolve. Here we present an assessment from both sides of the North Atlantic of differentiation among populations of a dolphin species that inhabits mainly pelagic waters, the Atlantic white-sided dolphin. We compare eleven putative populations in the western and eastern North Atlantic at mtDNA and microsatellite DNA loci and find reduced nucleotide diversity and signals for historical bottlenecks and post-bottleneck expansions in all regions. We calculate expansion times to have occurred during the early Holocene, following the last glacial maximum (LGM). We find evidence for connectivity among populations from either side of the North Atlantic, and differentiation between putative populations in the far northeast compared with all other areas sampled. Some data suggest the possibility of separate refugia during the LGM explaining this pattern, although ongoing ecological processes may also be a factor. We discuss the implications for developing effective programs of conservation and management in the context of ongoing anthropogenic impact. © 2014 Springer Science+Business Media Dordrecht.

  17. Atmospheric circulation in northern hemisphere and north atlantic oscillation

    Directory of Open Access Journals (Sweden)

    Александр Вадимович Холопцев

    2015-08-01

    Full Text Available Conditions under which statistical connections of interannual changes of repitition duration periods in Northern hemisphere of elementary circulation mechanisms associated to meridional northern and meridional southern groups with variations of North Atlantic oscillation are significant were revealed. It is shown, that the characteristics changes of these connections taking place in modern period can be caused by distribution changes of distribution of sea surface temperatures

  18. North Atlantic IFR Route Planning Chart GEO-TIFF - Aeronautical Information Services Digital Products

    Data.gov (United States)

    Department of Transportation — North Atlantic Route Chart is designed for FAA Controllers to monitor transatlantic flights, this 5-color chart shows oceanic control areas, coastal navigation aids,...

  19. North Atlantic IFR Route Planning Chart PDF File - Aeronautical Information Services Digital Products

    Data.gov (United States)

    Department of Transportation — North Atlantic Route Chart is designed for FAA Controllers to monitor transatlantic flights, this 5-color chart shows oceanic control areas, coastal navigation aids,...

  20. Projected future suitable habitat and productivity of Douglas-fir in western North America

    Science.gov (United States)

    Aaron R. Weiskittel; Nicholas L. Crookston; Gerald E. Rehfeldt

    2012-01-01

    Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) is one of the most common and commercially important species in western North America. The species can occupy a range of habitats, is long-lived (up to 500 years), and highly productive. However, the future of Douglas-fir in western North America is highly uncertain due to the expected changes in climate conditions....

  1. Toxocariasis in North America: a systematic review.

    Directory of Open Access Journals (Sweden)

    Rachel M Lee

    2014-08-01

    Full Text Available Toxocariasis is an important neglected tropical disease that can manifest as visceral or ocular larva migrans, or covert toxocariasis. All three forms pose a public health problem and cause significant morbidity in areas of high prevalence. To determine the burden of toxocariasis in North America, we conducted a systematic review of the literature following PRISMA guidelines. We found 18 articles with original prevalence, incidence, or case data for toxocariasis. Prevalence estimates ranged from 0.6% in a Canadian Inuit community to 30.8% in Mexican children with asthma. Commonly cited risk factors included: African-American race, poverty, male sex, and pet ownership or environmental contamination by animal feces. Increased prevalence of Toxocara spp. infection was linked in a group of case control studies conducted in Mexico to several high risk groups including waste pickers, asthmatic children, and inpatient psychiatry patients. Further research is needed to determine the true current burden of toxocariasis in North America; however the prevalence estimates gathered in this review suggest that the burden of disease is significant.

  2. Warm Water Pathways in the Northeastern North Atlantic ACCE RAFOS Float Data Report

    National Research Council Canada - National Science Library

    Furey, Heather

    2001-01-01

    ...). The RAFOS float component of ACCE, entitled "Warm Water Pathways and Intergyre Exchange in the Northeastern North Atlantic", was designed to measure the warm water currents entering the northeastern...

  3. Comparison of dental education and professional development between mainland China and North America.

    Science.gov (United States)

    Wu, Z Y; Zhang, Z Y; Jiang, X Q; Guo, L

    2010-05-01

    Different educational and professional developments within the dental field create different sets of missions, norms, and practices regarding dental diseases and their appropriate treatment. This review has addressed differences in dental education and professional development between mainland China and North America. Many factors influence the choice of model and it is very difficult to predict which model will become predominant. However, there is growing sentiment that the independent faculty model in North America is logical and superior to the model, which 'integrates' dental and medical education in mainland China. Many North America dental schools place a high priority on preclinical and clinical training in the curriculum in order to expose students to patient oral health needs and systemic dental problems much earlier than in mainland China. North America dental schools promote and embrace students self-learning skills by the use of PBL, CRL, and TRAD education methodologies and new e-based technologies and approaches whereby students learn rather than are taught. In mainland China, the traditional lecture-based format is still employed in the majority of dental schools; however, strategies to enhance students self-learning skills is increasingly utilised in most well-known Chinese dental schools. The Chinese dental education model, which treats dentistry as a sub-specialty of medicine, has brought about fundamental differences, with the dentist functioning essentially as a stomatologist. For example, China has built up a large oral and maxillofacial surgery society, and craniofacial surgery is performed to a much broader extent by Chinese dentists than by most North American counterparts. In North America, dentists engage in full-time work, attend continuing training/education programmes, belong to an association, gain legal status, and construct a code of ethics emphasising the quality of care delivered to the public. Currently, continuing dental

  4. North Atlantic near-surface salinity contrasts and intra-basin water vapor transfer

    Science.gov (United States)

    Reagan, J. R.; Seidov, D.; Boyer, T.

    2017-12-01

    The geographic distribution of near-surface salinity (NSS) in the North Atlantic is characterized by a very salty (>37) subtropical region contrasting with a much fresher (NSS. Additional results and potential implications will be presented and discussed.

  5. Thermal constraints on the emerald ash borer invasion of North America

    Science.gov (United States)

    DeSantis, R.; Moser, W. K.; Gormanson, D. D.; Bartlett, M. G.

    2012-12-01

    Emerald ash borer (Agrilus planipennis Fairmaire; EAB), a non-native invasive beetle, has caused substantial damage to green (Fraxinus pennsylvanica Marsh.), white (Fraxinus americana L.), and black ash (Fraxinus nigra Marsh.), the major ash species of North America. In the absence of effective methods for controlling or eradicating the beetle, EAB continues to spread unimpeded across North America. Evidence indicates the mortality rate for EAB-infested trees near the epicenter of the infestation in southeast Michigan exceeds 99 percent for the major ash species. One possible climatic limitation on the spread of the infestation is suggested by recent work indicating that beetles cannot survive exposure to temperatures below -35.3 degrees Celsius. We considered whether this thermal constraint will limit the spread and distribution of EAB in North America. Historical climatic data for the United States and Canada were employed along with thermal models of the conditions beneath likely winter snowpack and beneath tree bark to predict the potential geographic distribution of the invasion. Results suggested the thermal mortality constraint will not lead to the protection of ash stands across most of North America. However, recent work indicates the majority of beetles cannot survive exposure to temperatures below -30 degrees Celsius. Along with our results, this suggests thermal constraints near the northern and western edges of the ranges of ash might limit EAB survival to some extent, thereby reducing the EAB population, the likelihood of EAB infestation, and subsequent ash mortality.

  6. 75 FR 8921 - Grant of Authority for Subzone Status; Brightpoint North America L.P. (Cell Phone Kitting and...

    Science.gov (United States)

    2010-02-26

    ... Status; Brightpoint North America L.P. (Cell Phone Kitting and Distribution) Indianapolis, IN Pursuant to... the cell phone kitting and distribution facilities of Brightpoint North America L.P., located in... cell phones at the facilities of Brightpoint North America L.P., located in Plainfield, Indiana...

  7. Amplified North Atlantic Warming in the Late Pliocene by Changes in Arctic Gateways

    Science.gov (United States)

    Otto-Bliesner, B. L.; Jahn, A.; Feng, R.; Brady, E. C.; Hu, A.; Lofverstrom, M.

    2017-12-01

    Reconstructions of the late Pliocene (mid-Piacenzian, 3.3 - 3.0 million years ago) sea surface temperature (SST) find much warmer conditions in the North Atlantic than modern. The much warmer SSTs, up to 8.8°C from sites with good dating and replicates from several different types of proxies, have been difficult for climate models to reproduce. Even with the slow feedbacks of a reduced Greenland ice sheet and expansion of boreal forests to the Arctic Ocean over Canada and Eurasia, models cannot warm the North Atlantic sufficiently to match the reconstructed SSTs. An enhancement of the Atlantic Meridional Overturning Circulation (AMOC) during the late Pliocene, proposed as a possible mechanism based on ocean core records of δ13C, also is not present in the model simulations. Here, we present CESM simulations using a new reconstruction of late Pliocene paleogeography that has the Bering Strait (BS) and Canadian Arctic Archipelago (CAA) Straits closed. We find that the closure of these small Arctic gateways strengthens the AMOC, by inhibiting freshwater (FW) transport from the Pacific to the Arctic Ocean and from the Arctic Ocean to the Labrador Sea, leading to warmer sea surface temperatures in the North Atlantic. The cutoff of the short export route through the CAA results in a more saline Labrador and south Greenland Sea with increased deep convection. At the same time, as all FW now leaves the Arctic east of Greenland, there is a freshening of and decreased deepwater formation in the Norwegian Sea. Overall, the AMOC strengthens. This past time period has implications for a future Earth under more responsible scenarios of emissions. Late Pliocene atmospheric carbon dioxide concentrations are estimated to have ranged between 350 and 450 ppmv and the paleogeography is relatively similar to modern. Our study indicates that the state of the Arctic gateways may influence the sensitivity of the North Atlantic climate in complex ways, and better understanding of the

  8. Rapid Passenger Transport in North America in 21st Century

    Directory of Open Access Journals (Sweden)

    Wolf Tietze

    2012-10-01

    Full Text Available The occurrence of outstanding transport innovations maylead to monumental reconstruction in large urbanised regionssuch as North America. The decisive factor in this is the introductionofTransrapid, a new rapid transport technology basedon the principle of magnetic levitation (Maglev.This paper uses the urban network of North America Eastof the 1 O(Jh meridian, together with the smaller region of California,to demonstrate the advantages of innovative transporttechnology as the optimal link between road and air transport.Despite requiring less energy input, achieving better adaptationto the topography of the country, causing less noise and beingsubject to less wear and tear, Transrapid achieves almost twicethe speed of conventional trains.

  9. Distribution and population structure of North Atlantic harbour seals (Phoca vitulina

    Directory of Open Access Journals (Sweden)

    Liselotte Andersen

    2010-09-01

    Full Text Available A review of the known geographical distribution and current knowledge on the genetic population structure of harbour seals (Phoca vitulina in the North Atlantic is presented. Based on a synthesis of the results fromfive different studies of neutral geneticmarkers (mtDNAand nuclear microsatellites, mainly twelve genetically distinct populations were identified in the North Atlantic: USA/Canada, Iceland, west coast of Norway, Ireland-Scotland, English east coast, Channel area, Wadden Sea, Limfjord, Skagerrak, Kattegat, West Baltic, and East Baltic. Most of the studies addressed the population structure at the regional level, while only a few addressed the structuring at a local level, i.e. within countries. Due to the limited number of studies conducted, the identified population units were considered preliminary andmore detailed, local studieswould probably reveal structuring on a finer scale. The choice of genetic markers, their properties, resolution in time and applicability in population structure studies is shortly discussed and compared to ecological methods used to delineate populations.

  10. Soluble and colloidal iron in the oligotrophic North Atlantic and North Pacific.

    Science.gov (United States)

    Wu, J; Boyle, E; Sunda, W; Wen, L S

    2001-08-03

    In the oligotrophic North Atlantic and North Pacific, ultrafiltration studies show that concentrations of soluble iron and soluble iron-binding organic ligands are much lower than previously presumed "dissolved" concentrations, which were operationally defined as that passing through a 0.4-micrometer pore filter. Our studies indicate that substantial portions of the previously presumed "dissolved" iron (and probably also iron-binding ligands) are present in colloidal size range. The soluble iron and iron-binding organic ligands are depleted at the surface and enriched at depth, similar to distributions of major nutrients. By contrast, colloidal iron shows a maximum at the surface and a minimum in the upper nutricline. Our results suggest that "dissolved" iron may be less bioavailable to phytoplankton than previously thought and that iron removal through colloid aggregation and settling should be considered in models of the oceanic iron cycle.

  11. Status of soil acidification in North America

    Science.gov (United States)

    M. E. Fenn; T. G. Huntington; S. B. McLaughlin; C. Eagar; A. Gomez; R. B. Cook

    2006-01-01

    Forest soil acidification and depletion of nutrient cations have been reported for several forested regions in North America, predominantly in the eastern United States, including the northeast and in the central Appalachians, but also in parts of southeastern Canada and the southern U.S. Continuing regional inputs of nitrogen and sulfur are of concern because of...

  12. Current velocity and hydrographic observations in the Southwestern North Atlantic Ocean: Subtropical Atlantic Climate Studies (STACS), 1989 (NODC Accession 9100033)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The primary objective of the STACS program are to increase our understanding of the dynamics of the North Atlantic circulation and the role of the ocean circulation...

  13. 78 FR 40546 - Nissan North America, Incorporated, Receipt of Petition for Decision of Inconsequential...

    Science.gov (United States)

    2013-07-05

    ...-0142; Notice 1] Nissan North America, Incorporated, Receipt of Petition for Decision of Inconsequential...: Nissan North America, Inc. (Nissan) \\1\\ has determined that certain model year (MY) 2009 through 2012 Nissan Titan trucks manufactured from January 31, 2008 to July 17, 2012 and MY 2012 Nissan NV trucks...

  14. Identification of Holocene millennial-scale forcing in the North Atlantic area: Ocean/atmosphere contribution

    Science.gov (United States)

    Debret, M.; Masson-Delmotte, V.; Christophe, C.; de Vernal, A.; Massei, N.; Eynaud, F.; Nicolle, M.; Frank, N.; Mary, Y.; Magny, M.

    2017-12-01

    Millennial (1500-year) cycles were evidenced decades ago from the advance and retreat of glaciers but many subsequent studies failed to demonstrate the unequivocal character of such oscillation from paleoclimate time series. Hence, the identification of a persistent 1500 year periodicity remains controversial both for the last glacial episode and the Holocene. Applying wavelet analysis to Holocene climate records, we have identified synchronous millennial-scale oscillations which permit to establish a North Atlantic millennial variability index (NAV-Index), maximum at 5330 ± 245, 3560 ± 190, 1810 ± 160 cal years BP and minimum at 4430 ± 250, 2640 ± 225 and 970 ± 200 years before present. This NAV-index was compared with the millennial variability of cosmogenic 10Be isotope, a proxy of solar activity. Differences between the two sets of records suggest that an internal mechanism (Ocean/atmosphere) must be at the origin of the North Atlantic millennial scale variability. Our data document an increased coherence and magnitude of the North Atlantic millennial variability since 6000 cal. years BP, with a frequency of 1780 ± 240 years. During the early Holocene, deglacial meltwater fluxes had strong regional impact and the coupling between subpolar gyre migration and Atlantic meridional oceanic circulation observed since afterward seems to be related to the end of the Laurentide and Inuitian ice sheet meltwater discharge. Hence, we may conclude that the evolution of this millennial oscillation in the future will depend upon the Greenland stability or melting.

  15. An environmental model study of the deep layers of the North East Atlantic

    International Nuclear Information System (INIS)

    Bork, I.

    1989-01-01

    The field work of the north Atlantic monitoring Program (NOAMP) was supplemented by numerical simulations of the transport of radionuclides in the North Atlantic Ocean by annual mean flows and mixing processes. During the last year of NOAMP, a different attempt was made to compute the current field and three-dimensional trajectories of particles released in deep layers of the NOAMP area. It is the subject of this paper. The model used is of Bryan/Semtner type, but with smoothed topography and climatological (winter) temperature and salinity data. The results form a compromise between interpretation of climatological temperature and salinity data and the complete prediction of the current field by prognostic calculations, which yields a deep flow pattern that agrees with some ideas of the abyssal circulation

  16. Phytoplankton bloom and subpolar gyre induced dynamics in the North Atlantic

    DEFF Research Database (Denmark)

    Ferreira, Ana Sofia; Hátún, H.; Counillon, F.

    Several hypotheses have been promoted for phytoplankton bloom onset in the North Atlantic. First we show that the bloom dynamics in the northeastern corner stand out from the rest of the subpolar Atlantic, and thus warrants focused attention. We hypothesized that, for this region, late and weak...... blooms are expected in years of a strong subpolar gyre, i.e. strong atmospheric forcing, and cold and low saline conditions. We apply novel phenology algorithms to satellite ocean colour data, and analyse the outcome together with the subpolar gyre index. We find that the relationship between the bloom...

  17. The Carbon Budget of Coastal Waters of Eastern North America

    Science.gov (United States)

    Najjar, R.; Boyer, E. W.; Burdige, D.; Butman, D. E.; Cai, W. J.; Canuel, E. A.; Chen, R. F.; Friedrichs, M. A.; Griffith, P. C.; Herrmann, M.; Kemp, W. M.; Kroeger, K. D.; Mannino, A.; McCallister, S. L.; McGillis, W. R.; Mulholland, M. R.; Salisbury, J.; Signorini, S. R.; Tian, H.; Tzortziou, M.; Vlahos, P.; Wang, A. Z.; Zimmerman, R. C.; Pilskaln, C. H.

    2015-12-01

    Observations and the output of numerical and statistical models are synthesized to construct a carbon budget of the coastal waters of eastern North America. The domain extends from the head of tide to (roughly) the continental shelf break and from southern Florida to southern Nova Scotia. The domain area is 2% tidal wetlands, 19% estuarine open water, and 78% shelf water. Separate budgets are constructed for inorganic and organic carbon; for tidal wetlands, estuaries, and shelf waters; and for three main subregions: the Gulf of Maine, the Mid-Atlantic Bight, and the South Atlantic Bight. Net primary production for the study region is about 150 Tg C yr-1, with 12% occurring in tidal wetlands and 7% in estuaries. Though respiration and photosynthesis are nearly balanced in most systems and regions, tidal wetlands and shelf waters are each found to be net autotrophic whereas estuaries are net heterotrophic. The domain as a whole is a sink of 5 Tg C yr-1 of atmospheric CO2, with tidal wetlands and shelf waters taking up 10 Tg C yr-1 (split roughly equally) and estuaries releasing 5 Tg C yr-1 to the atmosphere. Carbon burial is about 3 Tg C yr-1, split roughly equally among tidal wetlands, estuaries, and shelf waters. Rivers supply 6-7 Tg C yr-1 to estuaries, about 2/3 of which is organic. Tidal wetlands supply an additional 4 Tg C yr-1 to estuaries, about half of which is organic. Carbon in organic and inorganic forms is exported from estuaries to shelf waters and from shelf waters to the open ocean. In summary, tidal wetlands and estuaries, though small in area, contribute substantially to the overall carbon budget of the region.

  18. Priorities for improving the scientific foundation of conservation policy in North America.

    Science.gov (United States)

    Noss, Reed F; Fleishman, Erica; Dellasala, Dominick A; Fitzgerald, John M; Gross, Mart R; Main, Martin B; Nagle, Fiona; O'Malley, Stacey L; Rosales, Jon

    2009-08-01

    The Society for Conservation Biology (SCB) can enhance conservation of biodiversity in North America by increasing its engagement in public policy. Toward this end, the North America Section of SCB is establishing partnerships with other professional organizations in order to speak more powerfully to decision makers and taking other actions--such as increasing interaction with chapters--geared to engage members more substantively in science-policy issues. Additionally, the section is developing a North American Biodiversity Blueprint, which spans the continental United States and Canada and is informed by natural and social science. This blueprint is intended to clarify the policy challenges for protecting continental biodiversity, to foster bilateral collaboration to resolve common problems, and to suggest rational alternative policies and practices that are more likely than current practices to sustain North America's natural heritage. Conservation scientists and practitioners can play a key role by drawing policy makers' attention to ultimate, as well as proximate, causes of biodiversity decline and to the ecological and economic consequences of not addressing these threats.

  19. Shifting Pacific storm tracks as stressors to ecosystems of western North America.

    Science.gov (United States)

    Dannenberg, Matthew P; Wise, Erika K

    2017-11-01

    Much of the precipitation delivered to western North America arrives during the cool season via midlatitude Pacific storm tracks, which may experience future shifts in response to climate change. Here, we assess the sensitivity of the hydroclimate and ecosystems of western North America to the latitudinal position of cool-season Pacific storm tracks. We calculated correlations between storm track variability and three hydroclimatic variables: gridded cool-season standardized precipitation-evapotranspiration index, April snow water equivalent, and water year streamflow from a network of USGS stream gauges. To assess how historical storm track variability affected ecosystem processes, we derived forest growth estimates from a large network of tree-ring widths and land surface phenology and wildfire estimates from remote sensing. From 1980 to 2014, cool-season storm tracks entered western North America between approximately 41°N and 53°N. Cool-season moisture supply and snowpack responded strongly to storm track position, with positive correlations to storm track latitude in eastern Alaska and northwestern Canada but negative correlations in the northwestern U.S. Ecosystems of the western United States were greener and more productive following winters with south-shifted storm tracks, while Canadian ecosystems were greener in years when the cool-season storm track was shifted to the north. On average, larger areas of the northwestern United States were burned by moderate to high severity wildfires when storm tracks were displaced north, and the average burn area per fire also tended to be higher in years with north-shifted storm tracks. These results suggest that projected shifts of Pacific storm tracks over the 21st century would likely alter hydroclimatic and ecological regimes in western North America, particularly in the northwestern United States, where moisture supply and ecosystem processes are highly sensitive to the position of cool-season storm tracks.

  20. The later evolution of modern sport in Latin America: the North American influence.

    Science.gov (United States)

    Arbena, J L

    2001-01-01

    American impact on modern sports in Latin America overlaps geographically and chronologically with the European, especially British, impact. Principally baseball in the Caribbean basin, more recently basketball and volleyball across the hemisphere and occasionally American football in more limited areas illustrate a north-to-south movement executed by businessmen, educators, missionaries, military personnel, returning travelers (often students), sports entrepreneurs and television. Often initially supported by promoters of development within Latin America, this transfer has altered local recreational patterns and attracted Latin athletes to pursue careers in North America, provoking accusations of cultural imperialism and exploitation.

  1. Winter Precipitation in North America and the Pacific-North America Pattern in GEOS-S2Sv2 Seasonal Hindcast

    Science.gov (United States)

    Li, Zhao; Molod, Andrea; Schubert, Siegfried

    2018-01-01

    Reliable prediction of precipitation remains one of the most pivotal and complex challenges in seasonal forecasting. Previous studies show that various large-scale climate modes, such as ENSO, PNA and NAO play significant role in winter precipitation variability over the Northern America. The influences are most pronounced in years of strong indices of such climate modes. This study evaluates model bias, predictability and forecast skills of monthly winter precipitation in GEOS5-S2S 2.0 retrospective forecast from 1981 to 2016, with emphasis on the forecast skill of precipitation over North America during the extreme events of ENSO, PNA and NAO by applying EOF and composite analysis.

  2. Invasion of Asian tiger shrimp, Penaeus monodon Fabricius, 1798, in the western north Atlantic and Gulf of Mexico

    Science.gov (United States)

    Fuller, Pam L.; Knott, David M.; Kingsley-Smith, Peter R.; Morris, James A.; Buckel, Christine A.; Hunter, Margaret E.; Hartman, Leslie D.

    2014-01-01

    After going unreported in the northwestern Atlantic Ocean for 18 years (1988 to 2006), the Asian tiger shrimp, Penaeus monodon, has recently reappeared in the South Atlantic Bight and, for the first time ever, in the Gulf of Mexico. Potential vectors and sources of this recent invader include: 1) discharged ballast water from its native range in Asia or other areas where it has become established; 2) transport of larvae from established non-native populations in the Caribbean or South America via ocean currents; or 3) escape and subsequent migration from active aquaculture facilities in the western Atlantic. This paper documents recent collections of P. monodon from the South Atlantic Bight and the Gulf of Mexico, reporting demographic and preliminary phylogenetic information for specimens collected between North Carolina and Texas from 2006 through 2012. The increased number of reports in 2011 and 2012, ranging from 102 mm to 298 mm total length, indicates that an adult population is present in densities sufficient for breeding, which is indicative of incipient establishment. Based on these reports of P. monodon, its successful invasion elsewhere, and its life history, we believe that this species will become common in the South Atlantic Bight and Gulf of Mexico in less than 10 years. Penaeus monodon is an aggressive predator in its native range and, if established, may prey on native shrimps, crabs, and bivalves. The impacts of an established P. monodon population are potentially widespread (e.g., alterations in local commercial fisheries, direct and indirect pressures on native shrimp, crab and bivalve populations, and subsequent impacts on the populations of other predators of those organisms) and should be considered by resource managers. The impacts of P. monodon on native fauna and the source(s) or vector(s) of the invasion, however, remain unknown at this time.

  3. Earth-Base: testing the temporal congruency of paleontological collections and geologic maps of North America

    Science.gov (United States)

    Heim, N. A.; Kishor, P.; McClennen, M.; Peters, S. E.

    2012-12-01

    Free and open source software and data facilitate novel research by allowing geoscientists to quickly and easily bring together disparate data that have been independently collected for many different purposes. The Earth-Base project brings together several datasets using a common space-time framework that is managed and analyzed using open source software. Earth-Base currently draws on stratigraphic, paleontologic, tectonic, geodynamic, seismic, botanical, hydrologic and cartographic data. Furthermore, Earth-Base is powered by RESTful data services operating on top of PostgreSQL and MySQL databases and the R programming environment, making much of the functionality accessible to third-parties even though the detailed data schemas are unknown to them. We demonstrate the scientific potential of Earth-Base and other FOSS by comparing the stated age of fossil collections to the age of the bedrock upon which they are geolocated. This analysis makes use of web services for the Paleobiology Database (PaleoDB), Macrostrat, the 2005 Geologic Map of North America (Garrity et al. 2009) and geologic maps of the conterminous United States. This analysis is a way to quickly assess the accuracy of temporal and spatial congruence of the paleontologic and geologic map datasets. We find that 56.1% of the 52,593 PaleoDB collections have temporally consistent ages with the bedrock upon which they are located based on the Geologic Map of North America. Surprisingly, fossil collections within the conterminous United States are more consistently located on bedrock with congruent geological ages, even though the USA maps are spatially and temporally more precise. Approximately 57% of the 37,344 PaleoDB collections in the USA are located on similarly aged geologic map units. Increased accuracy is attributed to the lumping of Pliocene and Quaternary geologic map units along the Atlantic and Gulf coastal plains in the Geologic Map of North America. The abundant Pliocene fossil collections

  4. Fostering renewable electricity markets in North America

    International Nuclear Information System (INIS)

    Wingate, M.; Hamrin, J.; Kvale, L.; Alatorre, C.

    2007-04-01

    This paper provided an overview of key market demand and supply drivers for the renewable electricity in Canada, the United States and Mexico. The aim of the paper was to assist North American governments in supporting the development of renewable electricity by addressing barriers that currently contribute to higher costs as well as challenges related to policy implementation. The paper outlined regulatory mandates and discussed issues related to voluntary purchases, and financial incentives. Current policy frameworks for renewable electricity were also examined. Opportunities for developing the renewable electricity market North America were explored. Wind power environmental standards were reviewed. Various green pricing schemes were discussed. The paper also included recommendations for the current electricity market as well as for members of the North American Agreement on Environmental Cooperation. 84 refs., 4 tabs., 7 figs

  5. US of tissue banking and transplantation in North America

    International Nuclear Information System (INIS)

    Strong, M.; Moogk, M.

    1999-01-01

    Tissue banking in North America began as surgical bone banking in individual hospitals and progressed to recovery of cadaveric tissues, initially by the United States Navy Tissue Bank and more recently to regional tissue banks throughout North America. The American Association of Tissue Banks was established in 1976 to develop standards for tissue banking and the eventual inspection and accreditation of tissue banks. The gathering of statistics of tissue banking practices was first undertaken in 1992, from accredited tissue banks. The most recent statistics were compiled in 1997 and will be reported at this conference.There are currently 63 accredited tissue banks in North America, 60 in the United States and three in Canada. Overall, tissue donation has increased by 48% during this 5 year reporting time. During the same period, the number of living surgical bone donors has decreased from nearly 3,000 to less than 500. This impact is largely due to the new regulations that have been implemented by the Food and Drug Administration (FDA). There were over 340,000 bone grafts distributed in 1996, an increase of 20% over 1992, 33% were not sterilized, 21% were sterilized using irradiation, and 45% were demineralized. Only 1% were processed using ethylene oxide as a sterilant, a decrease from 15% in 1992. The primary mode of preservation and storage is freeze-drying with 90% of the tissues falling into this category and the rest being frozen. The second largest number of grafts distributed were skin grafts. Total tissue grafts distributed including cornea was 445,417. In January 1998, the FDA Final Rule regarding regulation of tissue banking became effective. The elements of that Final Rule and new tissue banking rules the FDA has proposed will be discussed along with regulations recently published by the Health and Human Services Department relative to organ and tissue donor referrals. Tissue Banking in North America continues to evolve and has become more and more

  6. A51F-0123: Model Analysis of Tropospheric Aerosol Variability and Sources over the North Atlantic During NAAMES 2015-2016

    Science.gov (United States)

    Liu, Hongyu; Moore, Richard; Hostetler, Chris A.; Ferrare, Richard Anthony; Fairlie, Thomas Duncan; Hu, Youngxiang; Chen, Gao; Hair, Johnathan W.; Johnson, Matthew S.

    2016-01-01

    The North Atlantic Aerosols and Marine Ecosystems Study (NAAMES) is a five-year Earth-Venture Suborbital-2 Mission to characterize the plankton ecosystems and their influences on remote marine aerosols, boundary layer clouds, and their implications for climate in the North Atlantic. While marine-sourced aerosols have been shown to make important contributions to surface aerosol loading, cloud condensation nuclei and ice nuclei concentrations over remote marine and coastal regions, it is still a challenge to differentiate the marine biogenic aerosol signal from the strong influence of continental pollution outflow. We examine here the spatiotemporal variability and quantify the sources of tropospheric aerosols over the North Atlantic during the first two phases (November 2015 and May-June 2016) of NAAMES using a state-of-the-art chemical transport model (GEOS-Chem). The model is driven by the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) from the NASA Global Modeling and Assimilation Office (GMAO). It includes sulfate-nitrate-ammonium aerosol thermodynamics coupled to ozone-NOx-hydrocarbon-aerosol chemistry, mineral dust, sea salt, elemental and organic carbon aerosols, and especially a recently implemented parameterization for the marine primary organic aerosol emission. The simulated aerosols over the North Atlantic are evaluated with available satellite (e.g., MODIS) observations of aerosol optical depths (AOD), and aircraft and ship aerosol measurements. We diagnose transport pathways for continental pollution outflow over the North Atlantic using carbon monoxide, an excellent tracer for anthropogenic pollution transport. We also conduct model perturbation experiments to quantify the relative contributions of terrestrial and oceanic sources to the aerosol loading, AOD, and their variability over the North Atlantic.

  7. Atlantic small-mammal: a dataset of communities of rodents and marsupials of the Atlantic forests of South America.

    Science.gov (United States)

    Bovendorp, Ricardo S; Villar, Nacho; de Abreu-Junior, Edson F; Bello, Carolina; Regolin, André L; Percequillo, Alexandre R; Galetti, Mauro

    2017-08-01

    The contribution of small mammal ecology to the understanding of macroecological patterns of biodiversity, population dynamics, and community assembly has been hindered by the absence of large datasets of small mammal communities from tropical regions. Here we compile the largest dataset of inventories of small mammal communities for the Neotropical region. The dataset reviews small mammal communities from the Atlantic forest of South America, one of the regions with the highest diversity of small mammals and a global biodiversity hotspot, though currently covering less than 12% of its original area due to anthropogenic pressures. The dataset comprises 136 references from 300 locations covering seven vegetation types of tropical and subtropical Atlantic forests of South America, and presents data on species composition, richness, and relative abundance (captures/trap-nights). One paper was published more than 70 yr ago, but 80% of them were published after 2000. The dataset comprises 53,518 individuals of 124 species of small mammals, including 30 species of marsupials and 94 species of rodents. Species richness averaged 8.2 species (1-21) per site. Only two species occurred in more than 50% of the sites (the common opossum, Didelphis aurita and black-footed pigmy rice rat Oligoryzomys nigripes). Mean species abundance varied 430-fold, from 4.3 to 0.01 individuals/trap-night. The dataset also revealed a hyper-dominance of 22 species that comprised 78.29% of all individuals captured, with only seven species representing 44% of all captures. The information contained on this dataset can be applied in the study of macroecological patterns of biodiversity, communities, and populations, but also to evaluate the ecological consequences of fragmentation and defaunation, and predict disease outbreaks, trophic interactions and community dynamics in this biodiversity hotspot. © 2017 by the Ecological Society of America.

  8. The Development of improved willow clones for eastern North America

    Science.gov (United States)

    R. F. Kopp; L. B. Smart; C. A. Maynard; J. G. Isebrands; G. A. Tuskan; L. P. Abrahamson

    2001-01-01

    Efforts aimed at genetic improvement of Salix are increasing in North America.Most of these are directed towards developing improved clones for biomass production, phytoremediation, nutrient filters, and stream bank stabilization in the Northeast and North-central United States. Native species are of primary interest, but a small number of clones containing non-native...

  9. Radiotherapy for invasive breast cancer in North America and Europe: Results of a survey

    International Nuclear Information System (INIS)

    Ceilley, Elizabeth; Jagsi, Reshma; Goldberg, Saveli; Grignon, Laurent; Kachnic, Lisa; Powell, Simon; Taghian, Alphonse

    2005-01-01

    Purpose: To document and explain the current radiotherapeutic management of invasive breast cancer in North America and Europe. We also identified a number of areas of agreement, as well as controversy, toward which additional clinical research should be directed. Methods and materials: An original survey questionnaire was developed to assess radiation oncologists' self-reported management of breast cancer. The questionnaire was administered to physician members of the American Society for Therapeutic Radiology and Oncology and the European Society for Therapeutic Radiology and Oncology. We present the results of the comparative analysis of 702 responses from North America and 435 responses from Europe. Results: Several areas of national and international controversy were identified, including the selection of appropriate candidates for postmastectomy radiation therapy (RT) and the appropriate management of the regional lymph nodes after mastectomy, as well as after lumpectomy. Only 40.7% and 36.1% of respondents would use postmastectomy RT in patients with 1-3 positive lymph nodes in North America and Europe, respectively. Sentinel lymph node biopsy was offered more frequently by North American than European respondents (p < 0.0001) and more frequently by academic than nonacademic respondents in North America (p < 0.05). The average radiation fraction size was larger in Europe than in North America (p < 0.01). European respondents offered RT to the internal mammary chain more often than did the North American respondents (p < 0.001). North American respondents were more likely to offer RT to the supraclavicular fossa (p < 0.001) and axilla (p < 0.01). Conclusion: Marked differences were found in physician opinions regarding the management of breast cancer, with statistically significant international differences in patterns of care. This survey highlighted areas of controversy, providing support for international randomized trials to optimize the RT management of

  10. North Atlantic Origin of Interdecadal variability of Siberian High

    Science.gov (United States)

    Kim, Seon-Hwa; Sung, Mi-Kyung; Kim, Baek-Min

    2017-04-01

    We suggest that the changes in the mean atmospheric circulation structure in the North Atlantic Ocean upstream region of Eurasian continent play an important role in the interdecadal variability of Siberian High (SH) through the modulation of Ural blocking frequency. Previous studies suggested that the interdecadal variability of SH is partly explained by the Arctic Oscillation. However, in this study, we emphasize the role of 'Warm Arctic and Cold Eurasia (WACE)', which is the second mode of winter surface air temperature variability over Eurasia. We show that the correlation between SH and WACE is high in general compared to that between SH and AO. However, the correlation between SH and WACE does not always exhibit high constant value. It shows a distinctive interdecadal fluctuation in the correlation. We found that this fluctuation in the correlation is due to the interdecadal fluctuation of the continental trough over the North Atlantic and the resultant strengthening of in-situ atmospheric baroclinicity. This accompanies changes in the transient vorticity flux divergence which leads to the downstream wave development and anomalous anticyclonic flow near Ural region. Obviously, the existence of anticyclonic flow over Ural region helps more frequent occurrence of Ural blocking and it is shown that this condition favors positive WACE event, which links to an intensified SH.

  11. Interim oceanographic description of the North-East-Atlantic site for the disposal of low-level radioactive waste. Vol. 2

    International Nuclear Information System (INIS)

    Dickson, R.R.; Gurbutt, P.A.; Kershaw, P.J.

    1986-01-01

    The NEA Co-ordinated Research and Environmental Surveillance Programme (CRESP) related to sea disposal of radioactive waste was started in 1981 following a recommendation of the Group of experts convened every five years by NEA to review the continued suitability of the dumping site for radioactive waste in the North-East Atlantic. The objective of CRESP is to increase the available scientific data base related to the oceanographic and biological characteristics of the dump site and elaborate a site specific model of the transfers of radionuclides to human populations. Volume one of the ''Interim Oceanographic Description of the North-East Atlantic Site for the Disposal of Low-Level Radioactive Waste'' was published in early 1983. It was an attempt to identify remaining gaps in current knowledge of conditions at the site and relate these conditions to the physical environment of the North-East Atlantic Ocean as a whole. The amount of data obtained by the CRESP Programme is now sufficient to justify publication of this second volume. Scientists present results of research which is of direct relevance to a better assessment of the impact from dumping radioactive waste in the North-East Atlantic, in particular an evaluation of the potential radiation doses to man. These two volumes represent part of the scientific contribution of the CRESP Programme to the 1985 Review of the Continued Suitability of the North-East Atlantic dump site

  12. Modelling the future biogeography of North Atlantic zooplankton communities in response to climate change

    KAUST Repository

    Villarino, E; Chust, G; Licandro, P; Butenschö n, M; Ibaibarriaga, L; Larrañ aga, A; Irigoien, Xabier

    2015-01-01

    Advances in habitat and climate modelling allow us to reduce uncertainties of climate change impacts on species distribution. We evaluated the impacts of future climate change on community structure, diversity, distribution and phenology of 14 copepod species in the North Atlantic. We developed and validated habitat models for key zooplankton species using continuous plankton recorder (CPR) survey data collected at mid latitudes of the North Atlantic. Generalized additive models (GAMs) were applied to relate the occurrence of species to environmental variables. Models were projected to future (2080–2099) environmental conditions using coupled hydroclimatix–biogeochemical models under the Intergovernmental Panel on Climate Change (IPCC) A1B climate scenario, and compared to present (2001–2020) conditions. Our projections indicated that the copepod community is expected to respond substantially to climate change: a mean poleward latitudinal shift of 8.7 km per decade for the overall community with an important species range variation (–15 to 18 km per decade); the species seasonal peak is expected to occur 12–13 d earlier for Calanus finmarchicus and C. hyperboreus; and important changes in community structure are also expected (high species turnover of 43–79% south of the Oceanic Polar Front). The impacts of the change expected by the end of the century under IPCC global warming scenarios on copepods highlight poleward shifts, earlier seasonal peak and changes in biodiversity spatial patterns that might lead to alterations of the future North Atlantic pelagic ecosystem. Our model and projections are supported by a temporal validation undertaken using the North Atlantic climate regime shift that occurred in the 1980s: the habitat model built in the cold period (1970–1986) has been validated in the warm period (1987–2004).

  13. Modelling the future biogeography of North Atlantic zooplankton communities in response to climate change

    KAUST Repository

    Villarino, E

    2015-07-02

    Advances in habitat and climate modelling allow us to reduce uncertainties of climate change impacts on species distribution. We evaluated the impacts of future climate change on community structure, diversity, distribution and phenology of 14 copepod species in the North Atlantic. We developed and validated habitat models for key zooplankton species using continuous plankton recorder (CPR) survey data collected at mid latitudes of the North Atlantic. Generalized additive models (GAMs) were applied to relate the occurrence of species to environmental variables. Models were projected to future (2080–2099) environmental conditions using coupled hydroclimatix–biogeochemical models under the Intergovernmental Panel on Climate Change (IPCC) A1B climate scenario, and compared to present (2001–2020) conditions. Our projections indicated that the copepod community is expected to respond substantially to climate change: a mean poleward latitudinal shift of 8.7 km per decade for the overall community with an important species range variation (–15 to 18 km per decade); the species seasonal peak is expected to occur 12–13 d earlier for Calanus finmarchicus and C. hyperboreus; and important changes in community structure are also expected (high species turnover of 43–79% south of the Oceanic Polar Front). The impacts of the change expected by the end of the century under IPCC global warming scenarios on copepods highlight poleward shifts, earlier seasonal peak and changes in biodiversity spatial patterns that might lead to alterations of the future North Atlantic pelagic ecosystem. Our model and projections are supported by a temporal validation undertaken using the North Atlantic climate regime shift that occurred in the 1980s: the habitat model built in the cold period (1970–1986) has been validated in the warm period (1987–2004).

  14. Forest productivity in southwestern Europe is controlled by coupled North Atlantic and Atlantic Multidecadal Oscillations

    OpenAIRE

    Madrigal Gonzalez, Jaime; Ballesteros Canovas, Juan Antonio; Herrero, Asier; Ruiz-Benito, Paloma; Stoffel, Markus; Lucas-Borja, Manuel E.; Andivia, Enrique; Sancho-García, Cesar; Zavala, Miguel A.

    2017-01-01

    The North Atlantic Oscillation (NAO) depicts annual and decadal oscillatory modes of variability responsible for dry spells over the European continent. The NAO therefore holds a great potential to evaluate the role, as carbon sinks, of water-limited forests under climate change. However, uncertainties related to inconsistent responses of long-term forest productivity to NAO have so far hampered firm conclusions on its impacts. We hypothesize that, in part, such inconsistencies might have the...

  15. Prospects for exotic beam facilities in North America

    CERN Document Server

    Nolen, J A

    2002-01-01

    There are several nuclear physics laboratories in North America that have on-going research using energetic and stopped radioactive beams. These include the large ISOL-type programs ISAC at TRIUMF and HRIBF at Oak Ridge and the in-flight fragmentation program at the NSCL of Michigan State University. There are also smaller, more specialized, programs using a variety of techniques at the 88-inch cyclotron of Berkeley, ATLAS at Argonne, the Cyclotron Institute of Texas A&M University, the Nuclear Structure Laboratory at Notre Dame University, and the Nuclear Structure Laboratory at SUNY/Stony Brook. There are also three projects on the horizon in North America for new capabilities in both the near term and more distant future. The intensities of the in-flight fragment beams at the NSCL will be increased dramatically very soon as the Coupled Cyclotron Project will be completed and commissioned for research by mid-2001. A new project, ISAC-II, has been approved in Canada. For the longer term, the United State...

  16. Field Studies on Lyme Disease in North America

    Directory of Open Access Journals (Sweden)

    Joseph Piesman

    1991-01-01

    Full Text Available The primary tick vector of Borrelia burgdorferi in eastern and central North America is Ixodes dammini; in western North America, Ixodes pacificus. Searching for the appropriate vector is the first step in determining whether a region is endemic and enzootic for the spirochete B burgdorferi, the etiological agent of Lyme disease, followed by examination of the ticks (questing or already attached to hosts and wildlife for the spirochete. Questing ticks can be collected through a variety of methods. The two major animal hosts for I dammini are the white-footed mouse Peromyscus leucopus and the white-tailed deer Odocoileus virginianus. Sampling strategies should consider habitat and season. All three life stages of the vector tick should be located, indicating a self-sustaining population. Although B burgdorferi can be detected in many ways, there is no substitute for isolating the spirochete in Barbour-Stoenner-Kelly II medium for definitive proof of the presence of the Lyme disease spirochete.

  17. Linking size and age at sexual maturation to body growth, productivity and recruitment of Atlantic cod stocks spanning the North Atlantic

    DEFF Research Database (Denmark)

    Köster, Fritz; Trippel, E.A.; Tomkiewicz, Jonna

    2013-01-01

    Sexual maturation patterns of 22 North Atlantic stocks of cod (Gadus morhua) were examined and related to geographical distribution area, ambient water temperature, growth and surplus production. Four patterns were identified, i.e. sexual maturation early in life at small size, early in life...... Atlantic stocks. This comparative analysis suggests that maturation patterns relate to growth potential and surplus production whereas annual production of recruits per unit biomass appears unrelated to average size at sexual maturation...

  18. Global monthly CO2 flux inversion with a focus over North America

    International Nuclear Information System (INIS)

    Feng Deng; Chen, Jing M.; Ishizawa, Misa; Chiu-Wai Yuen; Gang Mo; Higuchi, Kaz; Chan, Douglas; Maksyutov, Shamil

    2007-01-01

    A nested inverse modelling system was developed for estimating carbon fluxes of 30 regions in North America and 20 regions for the rest of the globe. Monthly inverse modelling was conducted using CO 2 concentration measurements of 3 yr (2001-2003) at 88 sites. Inversion results show that in 2003 the global carbon sink is -2.76 ± 0.55 Pg C. Oceans and lands are responsible for 88.5% and 11.5% of the sink, respectively. Northern lands are the largest sinks with North America contributing a sink of -0.97 ± 0.21 Pg C in 2003, of which Canada's sink is -0.34 ± 0.14 Pg C. For Canada, the inverse results show a spatial pattern in agreement, for the most part, with a carbon source and sink distribution map previously derived through ecosystem modelling. However, discrepancies in the spatial pattern and in flux magnitude between these two estimates exist in certain regions. Numerical experiments with a full covariance matrix, with the consideration of the error structure of the a priori flux field based on meteorological variables among the 30 North America regions, resulted in a small but meaningful improvement in the inverted fluxes. Uncertainty reduction analysis suggests that new observation sites are still needed to further improve the inversion for these 30 regions in North America

  19. Downscaled Climate Model for the North Central Atlantic Ocean 2000-2100

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The regional MOM5 domain contain the Atlantic Ocean between 100°W and 20°E bounded north and south by 65°N and 20°S, respectively. The regional MOM5 will have a...

  20. 75 FR 69470 - Tele Atlas North America, Inc., Currently Doing Business as Tom Tom Including Off-Site Workers...

    Science.gov (United States)

    2010-11-12

    ...,839B; TA-W-70,839C] Tele Atlas North America, Inc., Currently Doing Business as Tom Tom Including Off... Business as Tom Tom, Concord, MA; Tele Atlas North America, Inc. Currently Doing Business as Tom Tom, Detroit, MI; Tele Atlas North America, Inc. Currently Doing Business as Tom Tom, Redwood, CA; Amended...

  1. Population structures of Astragalus filipes collections from western North America

    Science.gov (United States)

    B. Shaun Bushman; Kishor Bhattarai; Douglas A. Johnson

    2010-01-01

    The majority of species used for revegetation in semi-arid western rangelands of North America are grasses, with few forbs and nearly no legumes. Astragalus filipes (Torr. Ex A. Gray) is a western North American legume and a promising candidate for use in rangeland revegetation, but assessments of plant species diversity and structure are necessary to determine which...

  2. Regional assessment of North America: Urbanization trends, biodiversity patterns, and ecosystem services

    Science.gov (United States)

    McPhearson, Timon; Auch, Roger F.; Alberti, Marina

    2013-01-01

    North America contains some of the most urbanized landscapes in the world. In the United States (U.S.) and Canada, approximately 80 % of the population is urban, with Mexico slightly less (Kaiser Family Foundation 2013). Population growth combined with economic growth has fueled recent urban land expansion in North America. Between 1970 and 2000, urban land area expanded at a rate of 3.31 % (Seto et al. 2011) creating unique challenges for conserving biodiversity and maintaining regional and local ecosystem services.

  3. Ship Sensor Observations for North Atlantic Stepping Stones 2005 - Office of Ocean Exploration

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hourly measurements made by selected ship sensors on the NOAA ship Ronald H. Brown during the "North Atlantic Stepping Stones 2005" expedition sponsored by the...

  4. Estuarine Living Marine Resources: North Atlantic Regional Distribution and Abundance (NCEI Accession 0162402)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is the North Atlantic regional component of NOAA’s Estuarine Living Marine Resources (ELMR) Project, a national database of ecologically and economically...

  5. Nearshore marine benthic invertebrates moving north along the U.S. Atlantic coast

    Science.gov (United States)

    Numerous species have shifted their ranges north in response to global warming. We examined 21 years (1990-2010) of marine benthic invertebrate data from the National Coastal Assessment’s monitoring of nearshore waters along the US Atlantic coast. Data came from three bioge...

  6. Making full use of wind power potential in North America -- possibilities

    Energy Technology Data Exchange (ETDEWEB)

    Guillaud, Christian

    2010-09-15

    The anticipated increase in electrical load in North America up to the year 2050 will be at least 50%. Wind potential in North America is enormous, well in excess of the expected requirements. However, the amount of wind capacity, which can be directly connected to a grid is limited to 20% of the installed capacity because of technical constraints. Technologies to enable full wind potential to be harnessed still need to be developed; they will consist in storing wind energy in hydroelectric reservoirs or generating hydrogen. However, the resulting cost of electricity will be somewhat higher than present.

  7. Chronological history of zebra and quagga mussels (Dreissenidae) in North America, 1988-2010

    Science.gov (United States)

    Benson, Amy J.

    2013-01-01

    An unprecedented invasion began in North America in the mid-/late-1980s when two Eurasian mussel species, Dreissena polymorpha (zebra mussel) and Dreissena rostriformis bugensis (quagga mussel), became established in Laurentian Great Lakes. It is believed that Lake Erie was the initial location of establishment for both species, and within 3 years, zebra mussels had been found in all the Great Lakes. Since 1986, the combined distribution of two dreissenids has expanded throughout the Great Lakes region and the St. Lawrence River in Canada and also in the United States from the Great Lakes to the Mississippi Basin including Arkansas, Cumberland, Illinois, Missouri, Ohio, and Tennessee river basins. The distribution of dreissenid mussels in the Atlantic drainage has been limited to the Hudson and Susquehanna rivers. In the western United States, the quagga mussel established a large population in the lower Colorado River and spread to reservoirs in Arizona, California, Colorado, Nevada, and Utah. Overall, dreissenid species have been documented in 131 river systems and 772 inland lakes, reservoirs, and impoundments in the United States.

  8. Echinococcus multilocularis in North America: the great unknown

    Science.gov (United States)

    Massolo, Alessandro; Liccioli, Stefano; Budke, Christine; Klein, Claudia

    2014-01-01

    Over the last decade, studies have begun to shed light on the distribution and genetic characterization of Echinococcus multilocularis, the causative agent of alveolar echinococcosis (AE), in North America. Recent findings indicate that the parasite is likely expanding its range in the central region of the United States and Canada and that invasions of European strains might have occurred. In our review, we present the available data on E. multilocularis infections in wild and domestic animals and humans in North America and emphasize the lack of knowledge on the distribution of the parasite in wild and domestic hosts. Furthermore, we stress the need to better understand the complexity of host communities and their roles in shaping the transmission and distribution of the parasite. We hypothesize that a lack of knowledge about AE by North American physicians might result in the misdiagnosis of cases and an underestimation of disease incidence. The endemic presence of the parasite in urban areas and a recent human case in Alberta, Canada, suggest that the scientific community may need to reconsider the local public health risks, re-assess past cases that might have been overlooked and increase surveillance efforts to identify new cases of human AE. PMID:25531581

  9. Patterns of invasion and colonization of the sea lamprey (Petromyzon marinus) in North America as revealed by microsatellite genotypes.

    Science.gov (United States)

    Bryan, M B; Zalinski, D; Filcek, K B; Libants, S; Li, W; Scribner, K T

    2005-10-01

    Invasions by exotic organisms have had devastating affects on aquatic ecosystems, both ecologically and economically. One striking example of a successful invader that has dramatically affected fish community structure in freshwater lakes of North America is the sea lamprey (Petromyzon marinus). We used eight microsatellite loci and multiple analytical techniques to examine competing hypotheses concerning the origins and colonization history of sea lamprey (n = 741). Analyses were based on replicated invasive populations from Lakes Erie, Huron, Michigan, and Superior, populations of unknown origins from Lakes Ontario, Champlain, and Cayuga, and populations of anadromous putative progenitor populations in North America and Europe. Populations in recently colonized lakes were each established by few colonists through a series of genetic bottlenecks which resulted in lower allelic diversity in more recently established populations. The spatial genetic structure of invasive populations differed from that of native populations on the Atlantic coast, reflecting founder events and connectivity of invaded habitats. Anadromous populations were found to be panmictic (theta(P) = 0.002; 95% CI = -0.003-0.006; P > 0.05). In contrast, there was significant genetic differentiation between populations in the lower and upper Great Lakes (theta(P) = 0.007; P freshwater habitats were examined using coalescent-based analyses, and demonstrated that populations likely originated from natural migrations via the St Lawrence River.

  10. Twentieth century North Atlantic climate change. Part II: Understanding the effect of Indian Ocean warming

    Energy Technology Data Exchange (ETDEWEB)

    Hoerling, M.P.; Xu, T.; Bates, G.T. [Climate Diagnostics Center NOAA, Boulder, CO 80305-3328 (United States); Hurrell, J.W.; Phillips, A.S. [National Center for Atmospheric Research, Boulder, CO (United States)

    2004-09-01

    Ensembles of atmospheric general circulation model (AGCM) experiments are used in an effort to understand the boreal winter Northern Hemisphere (NH) extratropical climate response to the observed warming of tropical sea surface temperatures (SSTs) over the last half of the twentieth Century. Specifically, we inquire about the origins of unusual, if not unprecedented, changes in the wintertime North Atlantic and European climate that are well described by a linear trend in most indices of the North Atlantic Oscillation (NAO). The simulated NH atmospheric response to the linear trend component of tropic-wide SST change since 1950 projects strongly onto the positive polarity of the NAO and is a hemispheric pattern distinguished by decreased (increased) Arctic (middle latitude) sea level pressure. Progressive warming of the Indian Ocean is the principal contributor to this wintertime extratropical response, as shown through additional AGCM ensembles forced with only the SST trend in that sector. The Indian Ocean influence is further established through the reproducibility of results across three different models forced with identical, idealized patterns of the observed warming. Examination of the transient atmospheric adjustment to a sudden ''switch-on'' of an Indian Ocean SST anomaly reveals that the North Atlantic response is not consistent with linear theory and most likely involves synoptic eddy feedbacks associated with changes in the North Atlantic storm track. The tropical SST control exerted over twentieth century regional climate underlies the importance of determining the future course of tropical SST for regional climate change and its uncertainty. Better understanding of the extratropical responses to different, plausible trajectories of the tropical oceans is key to such efforts. (orig.)

  11. Explosive development of winter storm Xynthia over the subtropical North Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    M. L. R. Liberato

    2013-09-01

    Full Text Available In winter of 2009–2010 south-western Europe was hit by several destructive windstorms. The most important was Xynthia (26–28 February 2010, which caused 64 reported casualties and was classified as the 2nd most expensive natural hazard event for 2010 in terms of economic losses. In this work we assess the synoptic evolution, dynamical characteristics and the main impacts of storm Xynthia, whose genesis, development and path were very uncommon. Wind speed gusts observed at more than 500 stations across Europe are evaluated as well as the wind gust field obtained with a regional climate model simulation for the entire North Atlantic and European area. Storm Xynthia was first identified on 25 February around 30° N, 50° W over the subtropical North Atlantic Ocean. Its genesis occurred on a region characterized by warm and moist air under the influence of a strong upper level wave embedded in the westerlies. Xynthia followed an unusual SW–NE path towards Iberia, France and central Europe. The role of moist air masses on the explosive development of Xynthia is analysed by considering the evaporative sources. A lagrangian model is used to identify the moisture sources, sinks and moisture transport associated with the cyclone during its development phase. The main supply of moisture is located over an elongated region of the subtropical North Atlantic Ocean with anomalously high SST, confirming that the explosive development of storm Xynthia had a significant contribution from the subtropics.

  12. 75 FR 73159 - Continental Tire North America, Inc., Receipt of Petition for Decision of Inconsequential...

    Science.gov (United States)

    2010-11-29

    ...-0153; Notice 1] Continental Tire North America, Inc., Receipt of Petition for Decision of Inconsequential Noncompliance Continental Tire North America, Inc., (Continental),\\1\\ has determined that certain passenger car replacement tires manufactured in 2009 do not fully comply with paragraph S5.5(b) of Federal...

  13. Distribution of Polycystine Radiolarians in Bottom Surface Sediments and Its Relation to Summer Sea Temperature in the High-Latitude North Atlantic

    Directory of Open Access Journals (Sweden)

    Alexander Matul

    2017-10-01

    Full Text Available An objective of the study is to get new biogeographic information on the modern polycystine radiolarians from the high-latitude North Atlantic. The quantitative radiolarian dataset was compiled from publications and own micropaleontological counts from samples of the bottom surface sediments of the North Atlantic north of 40°N and Nordic Seas. Standard statistical treatment of micropaleontological data by factor analysis reveals five radiolarian assemblages which have their highest load at the specific temperature range in agreement with the oceanographic setting. An occurrence of radiolarian assemblages reflects extension and interaction of the warm North Atlantic and cold Polar/Arctic waters. Radiolarian distribution exhibits good correlation with the climatically averaged summer sea temperature on depth level of 200 m.

  14. Noise induced multidecadal variability in the North Atlantic: excitation of normal modes

    NARCIS (Netherlands)

    Frankcombe, L.M.; Dijkstra, H.A.; von der Heydt, A.S.

    2009-01-01

    In this paper it is proposed that the stochastic excitation of a multidecadal internal ocean mode is at the origin of the multidecadal sea surface temperature variability in the North Atlantic. The excitation processes of the spatial sea surface temperature pattern associated with this multidecadal

  15. Invasion by a Japanese marine microorganism in western North America

    Science.gov (United States)

    McGann, M.; Sloan, D.; Cohen, A.N.

    2000-01-01

    The earliest record in western North America of Trochammina hadai Uchio, a benthic foraminifer common in Japanese estuaries, is from sediment collected in Puget Sound in 1971. It was first found in San Francisco Bay in sediment samples taken in 1983, and since 1986 has been collected at 91% of the sampled sites in the Bay, constituting up to 93% of the foraminiferal assemblage at individual sites. The species is also present in recent sediment samples from 12 other sites along the west coast of North America. The evidence indicates that T. hadai is a recent introduction to San Francisco Bay, and is probably also not native to the other North American sites. Trochammina hadai was probably transported from Japan in ships' ballast tanks, in mud associated with anchors, or in sediments associated with oysters imported for mariculture. Its remarkable invasion of San Francisco Bay suggests the potential for massive, rapid invasions by other marine microorganisms.

  16. The genus Kochia (Chenopodiaceae) in North America

    Science.gov (United States)

    Ge-Lin Chu; Stewart Sanderson

    2008-01-01

    The genus Kochia and Bassia with which it has been combined, of Chenopodiaceae tribe Camphorosmeae, were at one time considered to include plants native to Eurasia, Australia, and North America, and included species of both C3 and C4 photosynthetic types. This aggregate has been reduced in size by removal of a large group of C3 Australian genera and species. Because of...

  17. The role of salinity in the decadal variability of the North Atlantic meridional overturning circulation

    Energy Technology Data Exchange (ETDEWEB)

    Frankignoul, Claude [Universite Pierre et Marie Curie, Paris 6, LOCEAN/IPSL, Paris Cedex 05 (France); Deshayes, Julie; Curry, Ruth [Woods Hole Oceanographic Institution, Woods Hole, MA (United States)

    2009-11-15

    An OGCM hindcast is used to investigate the linkages between North Atlantic Ocean salinity and circulation changes during 1963-2003. The focus is on the eastern subpolar region consisting of the Irminger Sea and the eastern North Atlantic where a careful assessment shows that the simulated interannual to decadal salinity changes in the upper 1,500 m reproduce well those derived from the available record of hydrographic measurements. In the model, the variability of the Atlantic meridional overturning circulation (MOC) is primarily driven by changes in deep water formation taking place in the Irminger Sea and, to a lesser extent, the Labrador Sea. Both are strongly influenced by the North Atlantic Oscillation (NAO). The modeled interannual to decadal salinity changes in the subpolar basins are mostly controlled by circulation-driven anomalies of freshwater flux convergence, although surface salinity restoring to climatology and other boundary fluxes each account for approximately 25% of the variance. The NAO plays an important role: a positive NAO phase is associated with increased precipitation, reduced northward salt transport by the wind-driven intergyre gyre, and increased southward flows of freshwater across the Greenland-Scotland ridge. Since the NAO largely controlled deep convection in the subpolar gyre, fresher waters are found near the sinking region during convective events. This markedly differs from the active influence on the MOC that salinity exerts at decadal and longer timescales in most coupled models. The intensification of the MOC that follows a positive NAO phase by about 2 years does not lead to an increase in the northward salt transport into the subpolar domain at low frequencies because it is cancelled by the concomitant intensification of the subpolar gyre which shifts the subpolar front eastward and reduces the northward salt transport by the North Atlantic Current waters. This differs again from most coupled models, where the gyre

  18. Eddy-driven stratification initiates North Atlantic spring phytoplankton blooms.

    Science.gov (United States)

    Mahadevan, Amala; D'Asaro, Eric; Lee, Craig; Perry, Mary Jane

    2012-07-06

    Springtime phytoplankton blooms photosynthetically fix carbon and export it from the surface ocean at globally important rates. These blooms are triggered by increased light exposure of the phytoplankton due to both seasonal light increase and the development of a near-surface vertical density gradient (stratification) that inhibits vertical mixing of the phytoplankton. Classically and in current climate models, that stratification is ascribed to a springtime warming of the sea surface. Here, using observations from the subpolar North Atlantic and a three-dimensional biophysical model, we show that the initial stratification and resulting bloom are instead caused by eddy-driven slumping of the basin-scale north-south density gradient, resulting in a patchy bloom beginning 20 to 30 days earlier than would occur by warming.

  19. 75 FR 76037 - HAVI Logistics, North America a Subsidiary of HAVI Group, LP Including On-Site Leased Workers of...

    Science.gov (United States)

    2010-12-07

    ... Logistics, North America a Subsidiary of HAVI Group, LP Including On-Site Leased Workers of Express Personnel Services and the La Salle Network, Bloomingdale, IL; Havi Logistics, North America, Lisle, IL..., applicable to workers of HAVI Logistics, North America, a subsidiary of HAVI Group, LP, including on-site...

  20. 78 FR 59090 - Nissan North America, Incorporated, Grant of Petition for Decision of Inconsequential Noncompliance

    Science.gov (United States)

    2013-09-25

    ...-0142; Notice 2] Nissan North America, Incorporated, Grant of Petition for Decision of Inconsequential.... SUMMARY: Nissan North America, Inc. (Nissan) has determined that certain model year (MY) 2009 through 2012 Nissan Titan trucks manufactured from January 31, 2008 to July 17, 2012 and MY 2012 Nissan NV trucks...

  1. 77 FR 24762 - Mitsubishi Motors North America, Inc., Grant of Petition for Decision of Inconsequential...

    Science.gov (United States)

    2012-04-25

    ... instruction standards. Refer to Hyundai Motor Company (74 FR 9125, March 2, 209); Ford Motor Company (73 FR 11462, March 3, 2008); Mazda North America Operations (73 FR 11464, March 3, 2008); Ford Motor Company...-0176; Notice 2] Mitsubishi Motors North America, Inc., Grant of Petition for Decision of...

  2. GLANAM (Glaciated North Atlantic Margins): A Marie Curie Initial Training Network between Norway, the UK & Denmark

    Science.gov (United States)

    Petter Sejrup, Hans; Oline Hjelstuen, Berit

    2015-04-01

    GLANAM (Glaciated North Atlantic Margins) is an Initial Training Network (ITN) funded under the EU Marie Curie Programme. It comprises 10 research partners from Norway, UK and Denmark, including 7 University research teams, 1 industrial full partner and 2 industrial associate partners. The GLANAM network will employ and train 15 early career researchers (Fellows). The aim of GLANAM is to improve the career prospects and development of young researchers in both the public and private sector within the field of earth science, focusing on North Atlantic glaciated margins. The young scientists will perform multi-disciplinary research and receive training in geophysics, remote sensing, GIS, sedimentology, geomorphology, stratigraphy, geochemistry and numerical modeling through three interconnected work packages that collectively address knowledge gaps related to the large, glacial age, sedimentary depocentres on the North Atlantic margin. The 15 Fellows will work on projects that geographically extend from Ireland in the south to the High Arctic. Filling these gaps will not only result in major new insights regarding glacial age processes on continental margins in general, but will also provide paleoclimate information essential for understanding the role of marine-based ice sheets in the climate system and for the testing of climate models. GLANAM brings together leading European research groups working on glaciated margins in a coordinated and collaborative research and training project. Focusing on the North Atlantic margins, this coordinated approach will lead to a major advance in the understanding of glaciated margins more widely and will fundamentally strengthen European research and build capacity in this field.

  3. Ecosystem carbon dioxide fluxes after disturbance in forests of North America

    Science.gov (United States)

    B. D. Amiro; A. G. Barr; J. G. Barr; T. A. Black; R. Bracho; al. et.

    2010-01-01

    [1] Disturbances are important for renewal of North American forests. Here we summarize more than 180 site years of eddy covariance measurements of carbon dioxide flux made at forest chronosequences in North America. The disturbances included standreplacing fire (Alaska, Arizona, Manitoba, and Saskatchewan) and harvest (British Columbia, Florida, New Brunswick, Oregon...

  4. Intraseasonal interaction between the Madden-Julian Oscillation and the North Atlantic Oscillation.

    Science.gov (United States)

    Cassou, Christophe

    2008-09-25

    Bridging the traditional gap between the spatio-temporal scales of weather and climate is a significant challenge facing the atmospheric community. In particular, progress in both medium-range and seasonal-to-interannual climate prediction relies on our understanding of recurrent weather patterns and the identification of specific causes responsible for their favoured occurrence, persistence or transition. Within this framework, I here present evidence that the main climate intra-seasonal oscillation in the tropics-the Madden-Julian Oscillation (MJO)-controls part of the distribution and sequences of the four daily weather regimes defined over the North Atlantic-European region in winter. North Atlantic Oscillation (NAO) regimes are the most affected, allowing for medium-range predictability of their phase far exceeding the limit of around one week that is usually quoted. The tropical-extratropical lagged relationship is asymmetrical. Positive NAO events mostly respond to a mid-latitude low-frequency wave train initiated by the MJO in the western-central tropical Pacific and propagating eastwards. Precursors for negative NAO events are found in the eastern tropical Pacific-western Atlantic, leading to changes along the North Atlantic storm track. Wave-breaking diagnostics tend to support the MJO preconditioning and the role of transient eddies in setting the phase of the NAO. I present a simple statistical model to quantitatively assess the potential predictability of the daily NAO index or the sign of the NAO regimes when they occur. Forecasts are successful in approximately 70 per cent of the cases based on the knowledge of the previous approximately 12-day MJO phase used as a predictor. This promising skill could be of importance considering the tight link between weather regimes and both mean conditions and the chances of extreme events occurring over Europe. These findings are useful for further stressing the need to better simulate and forecast the tropical

  5. 75 FR 80109 - Nissan North America, Inc., Receipt of Petition for Decision of Inconsequential Noncompliance

    Science.gov (United States)

    2010-12-21

    ...-0171; Notice 1] Nissan North America, Inc., Receipt of Petition for Decision of Inconsequential Noncompliance Nissan North America, Inc. (Nissan) \\1\\ has determined that certain model year 2008 through 2010 Nissan Titan trucks do not fully comply with the requirements of paragraph S19.2.2(b) of Federal Motor...

  6. Internal and external North Atlantic Sector variability in the Kiel climate model

    Energy Technology Data Exchange (ETDEWEB)

    Latif, Mojib; Park, Wonsun; Ding, Hui; Keenlyside, Noel S. [Leibniz-Inst. fuer Meereswissenschaften, Kiel (Germany)

    2009-08-15

    The internal and external North Atlantic Sector variability is investigated by means of a multimillennial control run and forced experiments with the Kiel Climate Model (KCM). The internal variability is studied by analyzing the control run. The externally forced variability is investigated in a run with periodic millennial solar forcing and in greenhouse warming experiments with enhanced carbon dioxide concentrations. The surface air temperature (SAT) averaged over the Northern Hemisphere simulated in the control run displays enhanced variability relative to the red background at decadal, centennial, and millennial timescales. Special emphasis is given to the variability of the Meridional Overturning Circulation (MOC). The MOC plays an important role in the generation of internal climate modes. Furthermore, the MOC provides a strong negative feedback on the Northern Hemisphere SAT in both the solar and greenhouse warming experiments, thereby moderating the direct effects of the external forcing in the North Atlantic. The implications of the results for decadal predictability are discussed. (orig.)

  7. Seasonal copepod lipid pump promotes carbon sequestration in the deep North Atlantic.

    Science.gov (United States)

    Jónasdóttir, Sigrún Huld; Visser, André W; Richardson, Katherine; Heath, Michael R

    2015-09-29

    Estimates of carbon flux to the deep oceans are essential for our understanding of global carbon budgets. Sinking of detrital material ("biological pump") is usually thought to be the main biological component of this flux. Here, we identify an additional biological mechanism, the seasonal "lipid pump," which is highly efficient at sequestering carbon into the deep ocean. It involves the vertical transport and metabolism of carbon rich lipids by overwintering zooplankton. We show that one species, the copepod Calanus finmarchicus overwintering in the North Atlantic, sequesters an amount of carbon equivalent to the sinking flux of detrital material. The efficiency of the lipid pump derives from a near-complete decoupling between nutrient and carbon cycling—a "lipid shunt," and its direct transport of carbon through the mesopelagic zone to below the permanent thermocline with very little attenuation. Inclusion of the lipid pump almost doubles the previous estimates of deep-ocean carbon sequestration by biological processes in the North Atlantic.

  8. Linking biotic homogenization to habitat type, invasiveness and growth form of naturalized alien plants in North America

    Science.gov (United States)

    Hong Qian; Qinfeng. Guo

    2010-01-01

    Aim Biotic homogenization is a growing phenomenon and has recently attracted much attention. Here, we analyse a large dataset of native and alien plants in North America to examine whether biotic homogenization is related to several ecological and biological attributes. Location North America (north of Mexico). Methods We assembled...

  9. Trophic impact of Atlantic bluefin tuna migrations in the North Sea

    DEFF Research Database (Denmark)

    Mariani, Patrizio; Andersen, Ken Haste; Lindegren, Martin

    2017-01-01

    and the stability of the fish community. The impact of a migrating top-predator is investigated here for Atlantic bluefin tuna in the North Sea. Bluefin tuna has been absent from the region for half-century, but recent years have seen recovery of migrations and a return of bluefin tuna in the area. We use a size...

  10. Mercury in the atmosphere, snow and melt water ponds in the North Atlantic Ocean during Arctic summer.

    Science.gov (United States)

    Aspmo, Katrine; Temme, Christian; Berg, Torunn; Ferrari, Christophe; Gauchard, L Pierre-Alexis; Fain, Xavier; Wibetoe, Grethe

    2006-07-01

    Atmospheric mercury speciation measurements were performed during a 10 week Arctic summer expedition in the North Atlantic Ocean onboard the German research vessel RV Polarstern between June 15 and August 29, 2004. This expedition covered large areas of the North Atlantic and Arctic Oceans between latitudes 54 degrees N and 85 degrees N and longitudes 16 degrees W and 16 degrees E. Gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and mercury associated with particles (Hg-P) were measured during this study. In addition, total mercury in surface snow and meltwater ponds located on sea ice floes was measured. GEM showed a homogeneous distribution over the open North Atlantic Ocean (median 1.53 +/- 0.12 ng/m3), which is in contrast to the higher concentrations of GEM observed over sea ice (median 1.82 +/- 0.24 ng/m3). It is hypothesized that this results from either (re-) emission of mercury contained in snow and ice surfaces that was previously deposited during atmospheric mercury depletion events (AMDE) in the spring or evasion from the ocean due to increased reduction potential at high latitudes during Arctic summer. Measured concentrations of total mercury in surface snow and meltwater ponds were low (all samples RGM and Hg-P without a significant diurnal variability. These results indicate that the production and deposition of these reactive mercury species do not significantly contribute to the atmospheric mercury cycle in the North Atlantic Ocean during the Arctic summer.

  11. Are Calanus spp. shifting poleward in the North Atlantic? A habitat modelling approach

    KAUST Repository

    Chust, Guillem; Castellani, Claudia; Licandro, Priscilla; Ibaibarriaga, Leire; Sagarminaga, Yolanda; Irigoien, Xabier

    2013-01-01

    is to verify the poleward shift of zooplankton species (Calanus finmarchicus, C. glacialis, C. helgolandicus, C. hyperboreus) for which distributional changes have been recorded in the North Atlantic Ocean and to assess how much of this shift was triggered

  12. Academic Talent Development in North America and Europe

    Science.gov (United States)

    Jarvin, Linda; Subotnik, Rena F.

    2015-01-01

    First we describe one particular model of talent development (Jarvin and Subotnik in The handbook of secondary gifted education. Prufrock Press, Waco, 2006) and situate it in perspective to other models developed in North America and Europe. We then discuss the implications of this view of giftedness on education and review related resources and…

  13. Regional Military Security Cooperation in North America

    Science.gov (United States)

    2009-12-11

    North America, Europe, Russia, Japan, South Korea, China, India , Australia, New Zealand, South Africa, Argentina, Brazil, and Chile.24 The Non...Sea.47 Additionally, he sees competition and conflict over water arising in the river basins of the Nile, Jordon, Tigris, and Euphrates rivers . This... interlinks with oil competition, as it is the same geographic region.48 Finally, he views Africa as an additional hot spot as there are many

  14. Drought-induced vegetation stress in southwestern North America

    International Nuclear Information System (INIS)

    Zhang Xiaoyang; Goldberg, Mitchell; Tarpley, Dan; Kogan, Felix; Yu Yunyue; Friedl, Mark A; Morisette, Jeffrey

    2010-01-01

    Trends towards earlier greenup and increased average greenness have been widely reported in both humid and dry ecosystems. By analyzing NOAA (National Oceanic and Atmospheric Administration) AVHRR (Advanced Very High Resolution Radiometer) data from 1982 to 2007, we report complex trends in both the growing season amplitude and seasonally integrated vegetation greenness in southwestern North America and further highlight regions consistently experiencing drought stress. In particular, greenness measurements from 1982 to 2007 show an increasing trend in grasslands but a decreasing trend in shrublands. However, vegetation greenness in this period has experienced a strong cycle, increasing from 1982 to 1993 but decreasing from 1993 to 2007. The significant decrease during the last decade has reduced vegetation greenness by 6% in shrublands and 13% in grasslands (16% and 21%, respectively, in the severe drought years). The greenness cycle correlates to both annual precipitation and dry season length derived from NOAA North America Regional Reanalysis data. If drought events continue as predicted by climate models, they will exacerbate ecosystem degradation and reduce carbon uptake.

  15. Potential for small-diameter sawtimber utilization by the current sawmill industry in western North America.

    Science.gov (United States)

    Francis G. Wagner; Charles E. Keegan; Roger D. Fight; Susan. Willits

    1998-01-01

    New silvicultural prescriptions for ecosystem management on both public and private timberlands in western North America will likely result in an influx of relatively small-diameter sawtimber for processing. Since sawmills currently process a majority of sawtimber harvested in western North America (more than 80% in some regions), this study concentrated on...

  16. New developments in canine hepatozoonosis in North America: a review

    Science.gov (United States)

    Little, Susan E; Allen, Kelly E; Johnson, Eileen M; Panciera, Roger J; Reichard, Mason V; Ewing, Sidney A

    2009-01-01

    Canine hepatozoonosis is caused by Hepatozoon canis and Hepatozoon americanum, apicomplexan parasites transmitted to dogs by ingestion of infectious stages. Although the two agents are phylogenetically related, specific aspects, including characteristics of clinical disease and the natural history of the parasites themselves, differ between the two species. Until recently, H. canis infections had not been clearly documented in North America, and autochthonous infection with H. americanum has yet to be reported outside of the southern United States. However, recent reports demonstrate H. canis is present in areas of North America where its vector tick, Rhipicephalus sanguineus, has long been endemic, and that the range of H. americanum is likely expanding along with that of its vector tick, Amblyomma maculatum; co-infections with the two organisms have also been identified. Significant intraspecific variation has been reported in the 18S rRNA gene sequence of both Hepatozoon spp.-infecting dogs, suggesting that each species may represent a complex of related genogroups rather than well-defined species. Transmission of H. americanum to dogs via ingestion of cystozoites in muscle of infected vertebrates was recently demonstrated, supporting the concept of predation as a means of natural transmission. Although several exciting advances have occurred in recent years, much remains to be learned about patterns of infection and the nature of clinical disease caused by the agents of canine hepatozoonosis in North America. PMID:19426444

  17. CO2 consumption and bicarbonate fluxes by chemical weathering in North America.

    Science.gov (United States)

    Jansen, Nils; Hartmann, Jens; Lauerwald, Ronny

    2010-05-01

    Cations released by chemical weathering are mainly counterbalanced by atmospheric/soil CO2 dissolved in water. Existing approaches to quantify CO2 consumption by chemical weathering are mostly based on the parameters runoff and lithology. Land cover is not implemented as predictor in existing regional or global scale models for atmospheric/soil CO2 consumption. Here, bicarbonate fluxes in North American rivers are quantified by an empirical forward model using the predictors runoff, lithology and land cover. The model was calibrated on chemical data from 338 river monitoring stations throughout North America. It was extrapolated to the entire North American continent by applying the model equation spatially explicitly to the geodata used for model calibration. Because silicate mineral weathering derived bicarbonate in rivers originates entirely from atmospheric/soil CO2, but carbonate mineral weathering additionally releases lithogenic bicarbonate, those source minerals are distinguished to quantify the CO2 consumption by chemical weathering. Extrapolation of the model results in a total bicarbonate flux of 51 Mt C a-1 in North America; 70% of which originate from atmospheric/soil CO2. On average, chemical weathering consumes 2.64 t atmospheric/soil C km-2 a-1 (~ 30%-40% above published world average values). For a given runoff and land cover, carbonate-rich sedimentary rocks export the most bicarbonate. However, half of this is assumed to be of lithogenic origin. Thus, the most atmospheric/soil CO2 per runoff is modeled to be consumed by basic plutonics. The least bicarbonate is exported and the least CO2 is consumed per runoff by weathering of metamorphic rocks. Of the distinguished different land cover classes of which urban areas export the most bicarbonate for a given lithology and runoff, followed by shrubs, grasslands and managed lands. For a given runoff and lithology, the least bicarbonate is exported from areas with forested land cover. The model shows 1

  18. 76 FR 67406 - Approval for Expanded Manufacturing Authority; Foreign-Trade Subzone 158D Nissan North America...

    Science.gov (United States)

    2011-11-01

    ... DEPARTMENT OF COMMERCE Foreign-Trade Zones Board [Order No. 1794] Approval for Expanded Manufacturing Authority; Foreign-Trade Subzone 158D Nissan North America, Inc.; (Motor Vehicles) Canton, MS...), the Foreign-Trade Zones Board (the Board) adopts the following Order. Whereas, Nissan North America...

  19. 75 FR 28297 - Sychip, Inc., a Wholly Owned Subsidiary of Murata Electronics North America, Inc. (MENA...

    Science.gov (United States)

    2010-05-20

    ... Owned Subsidiary of Murata Electronics North America, Inc. (MENA), Including Workers Whose Unemployment Insurance (UI) Wages Are Paid Through Either Adminstaff or MENA, Plano, TX; Amended Certification Regarding... owned subsidiary of Murata Electronics North America, Inc. (MENA). Since January 1, 2010, workers...

  20. Estimating the North Atlantic mean dynamic topography and geostrophic currents with GOCE

    DEFF Research Database (Denmark)

    Bingham, Rory J.; Knudsen, Per; Andersen, Ole Baltazar

    2011-01-01

    Three GOCE gravity models were released in July 2010 based on two months of observations. Subsequently, two second generation models, based on 8 months of observations, were released in March 2011. This paper compares these five models in terms of the mean North Atlantic circulation that can be d...

  1. Bayesian hierarchical modelling of North Atlantic windiness

    Directory of Open Access Journals (Sweden)

    E. Vanem

    2013-03-01

    Full Text Available Extreme weather conditions represent serious natural hazards to ship operations and may be the direct cause or contributing factor to maritime accidents. Such severe environmental conditions can be taken into account in ship design and operational windows can be defined that limits hazardous operations to less extreme conditions. Nevertheless, possible changes in the statistics of extreme weather conditions, possibly due to anthropogenic climate change, represent an additional hazard to ship operations that is less straightforward to account for in a consistent way. Obviously, there are large uncertainties as to how future climate change will affect the extreme weather conditions at sea and there is a need for stochastic models that can describe the variability in both space and time at various scales of the environmental conditions. Previously, Bayesian hierarchical space-time models have been developed to describe the variability and complex dependence structures of significant wave height in space and time. These models were found to perform reasonably well and provided some interesting results, in particular, pertaining to long-term trends in the wave climate. In this paper, a similar framework is applied to oceanic windiness and the spatial and temporal variability of the 10-m wind speed over an area in the North Atlantic ocean is investigated. When the results from the model for North Atlantic windiness is compared to the results for significant wave height over the same area, it is interesting to observe that whereas an increasing trend in significant wave height was identified, no statistically significant long-term trend was estimated in windiness. This may indicate that the increase in significant wave height is not due to an increase in locally generated wind waves, but rather to increased swell. This observation is also consistent with studies that have suggested a poleward shift of the main storm tracks.

  2. Bayesian hierarchical modelling of North Atlantic windiness

    Science.gov (United States)

    Vanem, E.; Breivik, O. N.

    2013-03-01

    Extreme weather conditions represent serious natural hazards to ship operations and may be the direct cause or contributing factor to maritime accidents. Such severe environmental conditions can be taken into account in ship design and operational windows can be defined that limits hazardous operations to less extreme conditions. Nevertheless, possible changes in the statistics of extreme weather conditions, possibly due to anthropogenic climate change, represent an additional hazard to ship operations that is less straightforward to account for in a consistent way. Obviously, there are large uncertainties as to how future climate change will affect the extreme weather conditions at sea and there is a need for stochastic models that can describe the variability in both space and time at various scales of the environmental conditions. Previously, Bayesian hierarchical space-time models have been developed to describe the variability and complex dependence structures of significant wave height in space and time. These models were found to perform reasonably well and provided some interesting results, in particular, pertaining to long-term trends in the wave climate. In this paper, a similar framework is applied to oceanic windiness and the spatial and temporal variability of the 10-m wind speed over an area in the North Atlantic ocean is investigated. When the results from the model for North Atlantic windiness is compared to the results for significant wave height over the same area, it is interesting to observe that whereas an increasing trend in significant wave height was identified, no statistically significant long-term trend was estimated in windiness. This may indicate that the increase in significant wave height is not due to an increase in locally generated wind waves, but rather to increased swell. This observation is also consistent with studies that have suggested a poleward shift of the main storm tracks.

  3. Climatic freshening of the deep North Atlantic (north of 500N) over the past 20 years. Final report

    International Nuclear Information System (INIS)

    Broecker, W.S.; Jenkins, W.J.; Rhines, P.B.; Rooth, C.G.; Swift, J.H.; Takahashi, T.; Williams, R.T.

    1982-01-01

    The Transient Tracers in the Ocean (TTO) program was initiated as a multi-institution, multi-year effort to study ocean transport processes by measuring the distributions of man-made trace substances as they penetrate into the oceans. During the first major field effort of the TTO program, we carried out a seven leg cruise in 1981, occupying 250 geochemical stations covering the North Atlantic from 15 0 N to Spitsbergen. Samples were taken for the measurement of tracers such as tritium (and its daughter 3 He) and 14 C which were produced by atmospheric nuclear weapons testing, and tracers that are byproducts of industrial activities, e.g. 85 Kr and trichlorofluoromethane. In addition, a series of precise measurements of nutrients, dissolved oxygen and hydrographic properties were made. We report here preliminary hydrographic results from the three most northerly legs, which show a temperature-salinity relationship throughout a large portion of the water volume north of 50 0 N systematically different from previously obtained (IGY) data. We contend that this difference is a result of a climatic variation in atmospheric and cryospheric conditions which manifest itself in a net change in the temperature and salinity characteristics of the overflow waters which supply the North Atlantic Deep Water masses. 11 references, 3 figures

  4. Uranium-thorium disequilibrium in north-east Atlantic waters

    International Nuclear Information System (INIS)

    Smith, K.J.; Leon Vintro, L.; Mitchell, P.I.; Bally de Bois, P.; Boust, D.

    2004-01-01

    In this paper we report and compare the concentrations of 234 Th and 238 U measured in surface and subsurface waters collected in the course of a sampling campaign in the north east Atlantic in June-July 1998. Dissolved 234 Th concentrations in surface waters ranged from 5 to 20 Bq m -3 , showing a large deficiency relative to 238 U concentrations (typically 42 Bq m -3 ). This disequilibrium is indicative of active 234 Th scavenging from surface waters. Observed 234 Th/ 238 U activity ratios, together with corresponding 234 Th particulate concentrations, were used to calculate mean residence times for 234 Th with respect to scavenging onto particles (τ diss ) and subsequent removal from surface waters (τ part ). Residence times in the range 5-30 days were determined for τ diss and 4-18 days for τ part (n=14). In addition, ultrafiltration experiments at six stations in the course of the same expedition revealed that in north-east Atlantic surface waters a significant fraction (46±17%; n=6) of the thorium in the (operationally-defined) dissolved phase ( 234 Th is rapidly absorbed by colloidal particles, which then aggregate, albeit at a slower rate, into larger filterable particles. In essence, colloids act as intermediaries in the transition from the fully dissolved to the filter-retained (>0.45 μm) phase. Thus, the time (τ c ) for fully dissolved 234 Th to appear in the filter-retained fraction is dependent on the rate of colloidal aggregation. Here, we determined τ c values in the range 3-17 days

  5. Antigenic Characterization of H3 Subtypes of Avian Influenza A Viruses from North America.

    Science.gov (United States)

    Bailey, Elizabeth; Long, Li-Ping; Zhao, Nan; Hall, Jeffrey S; Baroch, John A; Nolting, Jacqueline; Senter, Lucy; Cunningham, Frederick L; Pharr, G Todd; Hanson, Larry; Slemons, Richard; DeLiberto, Thomas J; Wan, Xiu-Feng

    2016-05-01

    Besides humans, H3 subtypes of influenza A viruses (IAVs) can infect various animal hosts, including avian, swine, equine, canine, and sea mammal species. These H3 viruses are both antigenically and genetically diverse. Here, we characterized the antigenic diversity of contemporary H3 avian IAVs recovered from migratory birds in North America. Hemagglutination inhibition (HI) assays were performed on 37 H3 isolates of avian IAVs recovered from 2007 to 2011 using generated reference chicken sera. These isolates were recovered from samples taken in the Atlantic, Mississippi, Central, and Pacific waterfowl migration flyways. Antisera to all the tested H3 isolates cross-reacted with each other and, to a lesser extent, with those to H3 canine and H3 equine IAVs. Antigenic cartography showed that the largest antigenic distance among the 37 avian IAVs is about four units, and each unit corresponds to a 2 log 2 difference in the HI titer. However, none of the tested H3 IAVs cross-reacted with ferret sera derived from contemporary swine and human IAVs. Our results showed that the H3 avian IAVs we tested lacked significant antigenic diversity, and these viruses were antigenically different from those circulating in swine and human populations. This suggests that H3 avian IAVs in North American waterfowl are antigenically relatively stable.

  6. Estimation of gas reserves in North America

    International Nuclear Information System (INIS)

    Laherrere, J.

    2001-01-01

    If the oil market is global, the gas market is divided into three zones: North America, Europe and Asia. The official forecast of the future demand of North America gas is optimist as it is based on estimates of resources which are ten times those of the proved reserves. The poor practice (SEC rules) of proved reserves (when the rest of the world uses proven+probable) leads to a constant revision and a growth of the past discoveries, showing well a wrong evaluation. The official databases are then very poor, even those of the US federal domain, which have to be public. The study of the technical data of reserves of US, Canada and Mexico leads to a more pessimistic estimation of the ultimate reserves and then to the future local supply. In the Gulf of Mexico (the main hope), the production of natural gas in shallow water decline and the discoveries in the deep-water are mainly oil. The non-conventional gas seems to level. But the future demand is also too optimistic, based on cheap price and on a steady growth. However the local gas supply will be likely insufficient, and the demand will need imported liquefied natural gas. (author)

  7. How well can fishes prey on zebra mussels in eastern North America?

    Science.gov (United States)

    French, John R. P.

    1993-01-01

    Literature on mollusk-eating fishes was reviewed to determine the potential for different species of fish to control zebra mussels in eastern North America. At least six species are potential predators of zebra mussels because they possess (1) both upper and lower pharyngeal teeth or (2) lower pharyngeal teeth and chewing pads located on the dorsal roof for crushing mollusk shells. Freshwater drum (Aplodinotus grunniens) and two centrarchids, redear sunfish (Lepomis microlophus) and pumpkinseed (L. gibbosus), possess both upper and lower pharyngeal teeth and are likely to consume more zebra mussels than fishes with only lower pharyngeal teeth. Only two catostomid species, copper and river redhorses (Moxostoma hubbsi and M. carinatum), have chewing pads that enable them to crush mollusks. The exotic omnivorous common carp (Cyprinus carpio), possessing lower teeth and a chewing pad, may prey on zebra mussels when aquatic insect larvae, its preferred food, become rare. Managing populations of drum, sunfishes and redhorses to reduce exploitation of large individuals and improve their habitats are suggested as means to intensify biological control of zebra mussels in eastern North America. Other Eurasian molluscivores, the roach (Rutilus rutilus) and the black carp (Mylopharyngodon piceus) should not be introduced into North America because research has shown repeatedly that an introduced biological controller usually does not forage for unwanted pests or reside only in preferred habitats of pests. Drum, sunfishes and redhorses should be preferred over these exotics as biological controllers of zebra mussels in North America because these native fishes will likely occupy newly established habitats of zebra mussels.

  8. Genetic calibration of species diversity among North America's freshwater fishes

    OpenAIRE

    April, Julien; Mayden, Richard L.; Hanner, Robert H.; Bernatchez, Louis

    2011-01-01

    Freshwater ecosystems are being heavily exploited and degraded by human activities all over the world, including in North America, where fishes and fisheries are strongly affected. Despite centuries of taxonomic inquiry, problems inherent to species identification continue to hamper the conservation of North American freshwater fishes. Indeed, nearly 10% of species diversity is thought to remain undescribed. To provide an independent calibration of taxonomic uncertainty and to establish a mor...

  9. Environmental radioactivity in the North Atlantic region. The Faroe Islands and Greenland included. 1983

    International Nuclear Information System (INIS)

    Aarkrog, A.; Boelskifte, S.; Buch, E.; Christensen, G.C.; Dahlgaard, H.; Hallstadius, L.; Hansen, H.; Holm, E.; Mattsson, S.; Meide, A.

    1984-12-01

    Measurements of fallout radioactivity in the North Atlantic region including the Faroe Islands and Greenland are reported. Strontium-90 and cesium-137 was determined in samples of precipitation, sea water, vegetation, various foodstuffs (including milk in the Faroes) and drinking water. Estimates are given of the mean contents of 90 Sr and 137 Cs in human diet in the Faroes and Greenland in 1983. Results from samplings of surface sea water and seaweed in the Norwegian and Greenland Seas and along the Norwegian and Greenland west coasts are reported. Beside radiocesium and 90 Sr some of these samples have also been anlysed for tritium,plutonium and americium. Finally technetium-99 data on seaweed samples collected in the North Atlantic region since the beginning of the sixties are presented. (author)

  10. Environmental radioactivity in the North Atlantic region. The Faroe Islands and Greenland included. 1984

    International Nuclear Information System (INIS)

    Aarkrog, A.; Boelskifte, S.; Buch, E.; Christensen, G.C.; Dahlgaard, H.; Hallstadius, L.; Hansen, H.; Holm, E.

    1985-12-01

    Measurements of fallout radioactivity in the North Atlantic region including the Faroe Islands and Greenland are reported. Strontium-90 and cesium-137 was determined in samples of precipitation, sea water, vegetation, various foodstuffs (including milk in the Faroes) and drinking water. Estimates are given of the mean contents of 90 Sr and 137 Cs in human diet in the Faroes and Greenland in 1984. Results from samplings of surface sea water and seaweed in the Norwegian and Greenland Seas and along the Norwegian and Greenland west coasts are reported. Beside radiocesium and 90 Sr some of these samples have also been anlysed for tritium, polonium, plutonium and americium. Finally technetium-99 data on seaweed samples collected in the North Atlantic region since the beginning of the sixties are presented. (author)

  11. Environmental radioactivity in the North Atlantic region. The Faroe Islands and Greenland included. 1985

    International Nuclear Information System (INIS)

    Aarkrog, A.; Boelskifte, S.; Dahlgaard, H.; Hansen, H.; Buch, E.; Christensen, G.C.; Hallstadius, L.; Rioseco, J.; Holm, E.

    1987-06-01

    Measurements of fallout radioactivity in the North Atlantic region including the Faroe Islands and Greenland are reported. Strontium-90 and cesium-137 was determined in samples of precipitation, sea water vegetation, various foodstuffs (including milk in the Faroes) and drinking water. Estimates are given of the mean contents of 90 Sr a 137 Cs in human diet in the Faroes and Greenland in 1985. Results from samplings of surface sea water and seaweed in the English Channel, the Fram Strait and along the Norwegian and Greenland coast are reported. Beside radiocesium and 90 Sr some of these samples have also been analysed for tritium, plutonium and americium. Finally technetium-99 data on seaweed and sea water samples collected in the North Atlantic region are presented. 14 refs. (author)

  12. Synchronisation of palaeoenvironmental events in the North Atlantic region during the last termination

    DEFF Research Database (Denmark)

    Lowe, John J.; Rasmussen, Sune Olander; Björck, Svante

    2008-01-01

    The North Atlantic INTIMATE group of the INQUA Palaeoclimate Commission has previously recommended an Event Stratigraphy approach for the synchronisation of records of the Last Termination using the Greenland GRIP isotopic record as the regional stratotype and INTCAL98 for the calibration...

  13. Emerging European winter precipitation pattern linked to atmospheric circulation changes over the North Atlantic region in recent decades

    Science.gov (United States)

    Ummenhofer, Caroline C.; Seo, Hyodae; Kwon, Young-Oh; Parfitt, Rhys; Brands, Swen; Joyce, Terrence M.

    2017-08-01

    Dominant European winter precipitation patterns over the past century, along with their associated extratropical North Atlantic circulation changes, are evaluated using cluster analysis. Contrary to the four regimes traditionally identified based on daily wintertime atmospheric circulation patterns, five distinct seasonal precipitation regimes are detected here. Recurrent precipitation patterns in each regime are linked to changes in atmospheric blocking, storm track, and sea surface temperatures across the North Atlantic region. Multidecadal variability in the frequency of the precipitation patterns reveals more (fewer) winters with wet conditions in northern (southern) Europe in recent decades and an emerging distinct pattern of enhanced wintertime precipitation over the northern British Isles. This pattern has become unusually common since the 1980s and is associated with changes in moisture transport and more frequent atmospheric river events. The observed precipitation changes post-1950 coincide with changes in storm track activity over the central/eastern North Atlantic toward the northern British Isles.

  14. Lessons learned from research and surveillance directed at highly pathogenic influenza A viruses in wild birds inhabiting North America.

    Science.gov (United States)

    Ramey, Andrew M; DeLiberto, Thomas J; Berhane, Yohannes; Swayne, David E; Stallknecht, David E

    2018-05-01

    Following detections of highly pathogenic (HP) influenza A viruses (IAVs) in wild birds inhabiting East Asia after the turn of the millennium, the intensity of sampling of wild birds for IAVs increased throughout much of North America. The objectives for many research and surveillance efforts were directed towards detecting Eurasian origin HP IAVs and understanding the potential of such viruses to be maintained and dispersed by wild birds. In this review, we highlight five important lessons learned from research and surveillance directed at HP IAVs in wild birds inhabiting North America: (1) Wild birds may disperse IAVs between North America and adjacent regions via migration, (2) HP IAVs can be introduced to wild birds in North America, (3) HP IAVs may cross the wild bird-poultry interface in North America, (4) The probability of encountering and detecting a specific virus may be low, and (5) Population immunity of wild birds may influence HP IAV outbreaks in North America. We review empirical support derived from research and surveillance efforts for each lesson learned and, furthermore, identify implications for future surveillance efforts, biosecurity, and population health. We conclude our review by identifying five additional areas in which we think future mechanistic research relative to IAVs in wild birds in North America are likely to lead to other important lessons learned in the years ahead. Published by Elsevier Inc.

  15. Lessons learned from research and surveillance directed at highly pathogenic influenza A viruses in wild birds inhabiting North America

    Science.gov (United States)

    Ramey, Andy M.; DeLiberto, Thomas J.; Berhane, Yohannes; Swayne, David E.; Stallknecht, David E.

    2018-01-01

    Following detections of highly pathogenic (HP) influenza A viruses (IAVs) in wild birds inhabiting East Asia after the turn of the millennium, the intensity of sampling of wild birds for IAVs increased throughout much of North America. The objectives for many research and surveillance efforts were directed towards detecting Eurasian origin HP IAVs and understanding the potential of such viruses to be maintained and dispersed by wild birds. In this review, we highlight five important lessons learned from research and surveillance directed at HP IAVs in wild birds inhabiting North America: (1) Wild birds may disperse IAVs between North America and adjacent regions via migration, (2) HP IAVs can be introduced to wild birds in North America, (3) HP IAVs may cross the wild bird-poultry interface in North America, (4) The probability of encountering and detecting a specific virus may be low, and (5) Population immunity of wild birds may influence HP IAV outbreaks in North America. We review empirical support derived from research and surveillance efforts for each lesson learned and, furthermore, identify implications for future surveillance efforts, biosecurity, and population health. We conclude our review by identifying five additional areas in which we think future mechanistic research relative to IAVs in wild birds in North America are likely to lead to other important lessons learned in the years ahead.

  16. Influence of Surface Processes over Africa on the Atlantic Marine ITCZ and South American Precipitation.

    Science.gov (United States)

    Hagos, Samson M.; Cook, Kerry H.

    2005-12-01

    Previous studies show that the climatological precipitation over South America, particularly the Nordeste region, is influenced by the presence of the African continent. Here the influence of African topography and surface wetness on the Atlantic marine ITCZ (AMI) and South American precipitation are investigated.Cross-equatorial flow over the Atlantic Ocean introduced by north south asymmetry in surface conditions over Africa shifts the AMI in the direction of the flow. African topography, for example, introduces an anomalous high over the southern Atlantic Ocean and a low to the north. This results in a northward migration of the AMI and dry conditions over the Nordeste region.The implications of this process on variability are then studied by analyzing the response of the AMI to soil moisture anomalies over tropical Africa. Northerly flow induced by equatorially asymmetric perturbations in soil moisture over northern tropical Africa shifts the AMI southward, increasing the climatological precipitation over northeastern South America. Flow associated with an equatorially symmetric perturbation in soil moisture, however, has a very weak cross-equatorial component and very weak influence on the AMI and South American precipitation. The sensitivity of the AMI to soil moisture perturbations over certain regions of Africa can possibly improve the skill of prediction.

  17. Holocene relative sea-level changes from North America and the Caribbean

    Science.gov (United States)

    Horton, Benjamin; Engelhart, Simon; Vacchi, Matteo; Khan, Nicole; Peltier, Dick; Roy, Keven

    2014-05-01

    Reconstructions of Holocene relative sea level (RSL) are important for identifying the ice equivalent meltwater contribution to sea-level change during deglaciation. Holocene RSL reconstructions from near, intermediate and far field regions enable the assessment of earth and ice parameters of Glacial Isostatic Adjustment (GIA) models. RSL reconstructions provide data for estimating rates of spatially variable and ongoing vertical land motion; a requirement for understanding the variation in modern and late Holocene sea level as recorded by instrumental and proxy records. Here we explain the methodology employed to reconstruct former sea levels, which follows the practice of the International Geoscience Programme (IGCP). We produce sea level index points from the Pacific and Atlantic coasts of North America and the Caribbean. Index points are defined as the most reliable observations of former sea levels. They consist of an estimate of X (age) and Y (the position of former RSL). Where a suite of index points are developed for a locality or region, they describe changes in RSL through time and estimate rates of change. A valid index point must meet the following four criteria; (1) location of the sample is known; (2) the altitude of the sample (and the error associated with measuring that altitude) is known; (3) the indicative meaning (the relationship between the sample and a tide level) is estimated; and (4) the age of the sample, which is commonly radiocarbon dated is calibrated to sidereal years using the latest calibration curves. In total databases have over 2000 sea-level index points from formerly ice covered, uplifting regions of Canada, to the region of forebulge collapse along the subsiding mid-Atlantic and mid-Pacific coastlines of the United States, to the tropical regions of the Caribbean. Recent analyses of these new published databases have led to a further refinement of the most recent of the ICE-NG (VMX) series of global models of GIA. The records

  18. Bat white-nose syndrome in North America

    Science.gov (United States)

    Blehert, David S.; Lorch, Jeffrey M.; Ballmann, Anne E.; Cryan, Paul M.; Meteyer, Carol U.

    2011-01-01

    * The newly described fungus, Geomyces destructans, causes an invasive skin infection in bats and is the likely agent of white-nose syndrome (WNS). * With immune system functions and body temperatures reduced during hibernation, bats may be unusually susceptible to a pathogenic fungus such as G. destructans. * WNS was first observed in a popular show cave near Albany, New York, leading some investigators to suspect that a visitor inadvertently introduced G. destructans at this site, triggering a wider WNS outbreak in North America. * Biologists trying to manage WNS within North American bat populations face major challenges, including the variety of susceptible host species, incredible dispersal capabilities of bats, difficulties in treating such populations, and persistence of the pathogen in their vulnerable underground habitats.

  19. The thrust belts of Western North America

    Energy Technology Data Exchange (ETDEWEB)

    Moulton, F.C.

    1993-08-01

    Most of the Basin and Range physiographic province of western North America is now believed to be part of the overthrust. The more obvious overthrust belt along the eastern edge of the Basin and Range Province is named the Sevier orogenic belt, where older rocks are observed thrust onto younger rocks. More detailed surface geological mapping, plus deep multiple-fold geophysical work and many oil and gas wildcat wells, have confirmed an east-vergent shortened and stacked sequence is present in many places in the Basin and Range. This western compressive deformed area in east central Nevada is now named the Elko orogenic belt by the U.S. Geological Survey. This older compressed Elko orogenic belt started forming approximately 250 m.y. ago when the North American plate started to move west as the Pangaea supercontinent started to fragment. The North American plate moved west under the sediments of the Miogeocline that were also moving west. Surface-formed highlands and oceanic island arcs on the west edge of the North American plate restricted the westward movement of the sediments in the Miogeocline, causing east-vergent ramp thrusts to form above the westward-moving North American plate. The flat, eastward-up-cutting thrust assemblages moved on the detachment surfaces.

  20. Punctuated Shutdown of Atlantic Meridional Overturning Circulation during Greenland Stadial 1

    Science.gov (United States)

    Hogg, Alan; Southon, John; Turney, Chris; Palmer, Jonathan; Bronk Ramsey, Christopher; Fenwick, Pavla; Boswijk, Gretel; Friedrich, Michael; Helle, Gerhard; Hughen, Konrad; Jones, Richard; Kromer, Bernd; Noronha, Alexandra; Reynard, Linda; Staff, Richard; Wacker, Lukas

    2016-01-01

    The Greenland Stadial 1 (GS-1; ~12.9 to 11.65 kyr cal BP) was a period of North Atlantic cooling, thought to have been initiated by North America fresh water runoff that caused a sustained reduction of North Atlantic Meridional Overturning Circulation (AMOC), resulting in an antiphase temperature response between the hemispheres (the ‘bipolar seesaw’). Here we exploit sub-fossil New Zealand kauri trees to report the first securely dated, decadally-resolved atmospheric radiocarbon (14C) record spanning GS-1. By precisely aligning Southern and Northern Hemisphere tree-ring 14C records with marine 14C sequences we document two relatively short periods of AMOC collapse during the stadial, at ~12,920-12,640 cal BP and 12,050-11,900 cal BP. In addition, our data show that the interhemispheric atmospheric 14C offset was close to zero prior to GS-1, before reaching ‘near-modern’ values at ~12,660 cal BP, consistent with synchronous recovery of overturning in both hemispheres and increased Southern Ocean ventilation. Hence, sustained North Atlantic cooling across GS-1 was not driven by a prolonged AMOC reduction but probably due to an equatorward migration of the Polar Front, reducing the advection of southwesterly air masses to high latitudes. Our findings suggest opposing hemispheric temperature trends were driven by atmospheric teleconnections, rather than AMOC changes. PMID:27194601

  1. Impact of millennial-scale Holocene climate variability on eastern North American terrestrial ecosystems: Pollen-based climatic reconstruction

    Science.gov (United States)

    Willard, D.A.; Bernhardt, C.E.; Korejwo, D.A.; Meyers, S.R.

    2005-01-01

    We present paleoclimatic evidence for a series of Holocene millennial-scale cool intervals in eastern North America that occurred every ???1400 years and lasted ???300-500 years, based on pollen data from Chesapeake Bay in the mid-Atlantic region of the United States. The cool events are indicated by significant decreases in pine pollen, which we interpret as representing decreases in January temperatures of between 0.2??and 2??C. These temperature decreases include excursions during the Little Ice Age (???1300-1600 AD) and the 8 ka cold event. The timing of the pine minima is correlated with a series of quasi-periodic cold intervals documented by various proxies in Greenland, North Atlantic, and Alaskan cores and with solar minima interpreted from cosmogenic isotope records. These events may represent changes in circumpolar vortex size and configuration in response to intervals of decreased solar activity, which altered jet stream patterns to enhance meridional circulation over eastern North America. ?? 2004 Elsevier B.V. All rights reserved.

  2. 2014 outbreak of enterovirus D68 in North America.

    Science.gov (United States)

    Messacar, Kevin; Abzug, Mark J; Dominguez, Samuel R

    2016-05-01

    Enterovirus D68 (EV-D68) is an emerging picornavirus which causes severe respiratory disease, predominantly in children. In 2014, the largest and most widespread outbreak of EV-D68 described to date was reported in North America. Hospitals throughout the United States and Canada reported surges in patient volumes and resource utilization from August to October, 2014. In the US a total of 1,153 infections were confirmed in 49 states, although this is an underestimate of the likely millions of cases that occurred but were not tested. EV-D68 was detected in 14 patients who died; the role of the virus in these deaths is unknown. A possible association between EV-D68 and cases of acute flaccid paralysis with spinal cord gray matter lesions, known as acute flaccid myelitis, was observed during the outbreak and is under investigation. The 2014 outbreak of EV-D68 in North America demonstrates the public health importance of this emerging pathogen. © 2015 Wiley Periodicals, Inc.

  3. A New Eocene Casquehead Lizard (Reptilia, Corytophanidae from North America.

    Directory of Open Access Journals (Sweden)

    Jack L Conrad

    Full Text Available A new fossil showing affinities with extant Laemanctus offers the first clear evidence for a casquehead lizard (Corytophanidae from the Eocene of North America. Along with Geiseltaliellus from roughly coeval rocks in central Europe, the new find further documents the tropical fauna present during greenhouse conditions in the northern mid-latitudes approximately 50 million years ago (Ma. Modern Corytophanidae is a neotropical clade of iguanian lizards ranging from southern Mexico to northern South America.

  4. A Glacial Perspective on the Impact of Heinrich Stadials on North Atlantic Climate

    Science.gov (United States)

    Bromley, G. R.; Putnam, A. E.; Rademaker, K. M.; Balter, A.; Hall, B. L.

    2017-12-01

    The British Isles contain a rich geologic record of Late Pleistocene ice sheet behaviour in the NE North Atlantic basin. We are using cosmogenic 10Be surface-exposure dating, in conjunction with detailed glacial-geomorphic mapping, to reconstruct the timing and nature of cryospheric change - and thus climate variability - in northern Scotland since the Last Glacial Maximum. Our specific focus is Heinrich Stadial 1 (18,300-14,700 years ago), arguably the most significant abrupt climate event of the last glacial cycle and a major feature in global palaeoclimate records. Such constraint is needed because of currently conflicting models of how these events impact terrestrial environments and a recent hypothesis attributing this disparity to enhanced seasonality in the North Atlantic basin. To date, we have measured 10Be in > 30 samples from glacial erratics located on moraines deposited by the British Ice Sheet as it retreated from the continental shelf to its highland source regions. Our preliminary results indicate that the stadial was characterised by widespread deglaciation driven by atmospheric warming, a pattern that is suggestive of pronounced seasonality. Additionally, we report new exposure ages from moraines deposited during a subsequent phase of alpine glaciation (known locally as the Loch Lomond Readvance) that has long been attributed to the Younger Dryas stadial. With the growing focus on the full expression of stadials, and the inherent vulnerability of Europe to shifts in North Atlantic climate, developing the extant record of terrestrial glaciation and comparing these data to marine records is a critical step towards understanding the drivers of abrupt climate change.

  5. Ecological, morphological and genetic divergence of sympatric North Atlantic killer whale populations

    DEFF Research Database (Denmark)

    Foote, Andrew D; Newton, Jason; Piertney, Stuart B

    2009-01-01

    promoting divergence. Here we use morphological traits, nitrogen stable isotope ratios and tooth wear to characterize two disparate types of North Atlantic killer whale. We find a highly specialist type, which reaches up to 8.5 m in length and a generalist type which reaches up to 6.6 m in length...

  6. Synoptic-scale analysis of mechanisms driving surface chlorophyll dynamics in the North Atlantic

    DEFF Research Database (Denmark)

    Ferreira, Ana Sofia; Hatun, H.; Counillon, F.

    2015-01-01

    show that, in terms of bottom-up processes alone, there is a dominant physical mechanism, namely mixed-layer shoaling, that best predicts the interannual variation in the initial increase in surface chlorophyll across large sectors of the North Atlantic. We further show that different regions...

  7. Impacts of the north and tropical Atlantic Ocean on the Antarctic Peninsula and sea ice.

    Science.gov (United States)

    Li, Xichen; Holland, David M; Gerber, Edwin P; Yoo, Changhyun

    2014-01-23

    In recent decades, Antarctica has experienced pronounced climate changes. The Antarctic Peninsula exhibited the strongest warming of any region on the planet, causing rapid changes in land ice. Additionally, in contrast to the sea-ice decline over the Arctic, Antarctic sea ice has not declined, but has instead undergone a perplexing redistribution. Antarctic climate is influenced by, among other factors, changes in radiative forcing and remote Pacific climate variability, but none explains the observed Antarctic Peninsula warming or the sea-ice redistribution in austral winter. However, in the north and tropical Atlantic Ocean, the Atlantic Multidecadal Oscillation (a leading mode of sea surface temperature variability) has been overlooked in this context. Here we show that sea surface warming related to the Atlantic Multidecadal Oscillation reduces the surface pressure in the Amundsen Sea and contributes to the observed dipole-like sea-ice redistribution between the Ross and Amundsen-Bellingshausen-Weddell seas and to the Antarctic Peninsula warming. Support for these findings comes from analysis of observational and reanalysis data, and independently from both comprehensive and idealized atmospheric model simulations. We suggest that the north and tropical Atlantic is important for projections of future climate change in Antarctica, and has the potential to affect the global thermohaline circulation and sea-level change.

  8. Jurassic domes in the North Sea - northern North Atlantic region

    Energy Technology Data Exchange (ETDEWEB)

    Surlyk, F. [Univ. of Copenhagen, Geological Inst., Copenhagen (Denmark)

    1996-12-31

    subsequent deflation played a major role in the formation of completely separate Boreal and Tethyan faunal provinces in Bajocian-Bathonian time followed by gradual re-establishment of faunal connection in the Early Callovian. The Middle Jurassic unconformities of the northwest European North Atlantic region reflect a tectonic phase in the break-up of Pangaea with development of volcanic rift domes of major importance for drainage patterns, palaeoceanography, palaeobiogeography and implicatly biostratigraphic correlation. (au) Appendix no. 11. 63 refs.

  9. Necrotizing Fasciitis Caused by Hypermucoviscous Klebsiella pneumoniae in a Filipino Female in North America

    Directory of Open Access Journals (Sweden)

    Ng, Daniel

    2014-12-01

    Full Text Available Necrotizing fasciitis caused by Klebsiella pneumoniae has been described in Southeast Asia, but has only recently begun to emerge in North America. The hypermucoviscous strain of K. pneumoniae is a particularly virulent strain known to cause devastatingly invasive infections, including necrotizing fasciitis. Here we present the first known case of necrotizing fasciitis caused by hypermucoviscous K. pneumoniae in North America. [West J Emerg Med. 2015;16(1:165–168.

  10. Recent Rates of Forest Harvest and Conversion in North America

    Science.gov (United States)

    Masek, Jeffrey G.; Cohen, Warren B.; Leckie, Donald; Wulder, Michael A.; Vargas, Rodrigo; de Jong, Ben; Healey, Sean; Law, Beverly; Birdsey, Richard; Houghton, R. A.; hide

    2011-01-01

    Incorporating ecological disturbance into biogeochemical models is critical for estimating current and future carbon stocks and fluxes. In particular, anthropogenic disturbances, such as forest conversion and wood harvest, strongly affect forest carbon dynamics within North America. This paper summarizes recent (2000.2008) rates of extraction, including both conversion and harvest, derived from national forest inventories for North America (the United States, Canada, and Mexico). During the 2000s, 6.1 million ha/yr were affected by harvest, another 1.0 million ha/yr were converted to other land uses through gross deforestation, and 0.4 million ha/yr were degraded. Thus about 1.0% of North America fs forests experienced some form of anthropogenic disturbance each year. However, due to harvest recovery, afforestation, and reforestation, the total forest area on the continent has been roughly stable during the decade. On average, about 110 m3 of roundwood volume was extracted per hectare harvested across the continent. Patterns of extraction vary among the three countries, with U.S. and Canadian activity dominated by partial and clear ]cut harvest, respectively, and activity in Mexico dominated by conversion (deforestation) for agriculture. Temporal trends in harvest and clearing may be affected by economic variables, technology, and forest policy decisions. While overall rates of extraction appear fairly stable in all three countries since the 1980s, harvest within the United States has shifted toward the southern United States and away from the Pacific Northwest.

  11. North Atlantic deep water formation and AMOC in CMIP5 models

    Directory of Open Access Journals (Sweden)

    C. Heuzé

    2017-07-01

    Full Text Available Deep water formation in climate models is indicative of their ability to simulate future ocean circulation, carbon and heat uptake, and sea level rise. Present-day temperature, salinity, sea ice concentration and ocean transport in the North Atlantic subpolar gyre and Nordic Seas from 23 CMIP5 (Climate Model Intercomparison Project, phase 5 models are compared with observations to assess the biases, causes and consequences of North Atlantic deep convection in models. The majority of models convect too deep, over too large an area, too often and too far south. Deep convection occurs at the sea ice edge and is most realistic in models with accurate sea ice extent, mostly those using the CICE model. Half of the models convect in response to local cooling or salinification of the surface waters; only a third have a dynamic relationship between freshwater coming from the Arctic and deep convection. The models with the most intense deep convection have the warmest deep waters, due to a redistribution of heat through the water column. For the majority of models, the variability of the Atlantic Meridional Overturning Circulation (AMOC is explained by the volumes of deep water produced in the subpolar gyre and Nordic Seas up to 2 years before. In turn, models with the strongest AMOC have the largest heat export to the Arctic. Understanding the dynamical drivers of deep convection and AMOC in models is hence key to realistically forecasting Arctic oceanic warming and its consequences for the global ocean circulation, cryosphere and marine life.

  12. The relation between AMOC, gyre circulation, and meridional heat transports in the North Atlantic in model simulations of the last millennium

    Science.gov (United States)

    Jungclaus, Johann; Moreno-Chamarro, Eduardo; Lohmann, Katja

    2016-04-01

    While it is clear that the Atlantic Meridional Overturning Circulation (AMOC) is responsible for meridional heat transfer from the South Atlantic and the tropics to the North Atlantic, the majority of the heat transport in the northern North Atlantic and the Nordic seas is carried by the gyre system. However, the detailed mechanisms determining the interaction between and the temporal modulation of the components of the northward heat transport system are not clear. Long-term climate records and model simulations can help to identify important processes and to provide background for the changes that are presently observed. Multi-centennial proxy records from the subpolar North Atlantic and the Nordic Seas indicate, for example, an out-of-phase behavior of sea surface temperature and gyre circulation between the two regions with consequences for regional climate. Paleoceanographic evidence from Fram Strait shows a pronounced modulation of heat transfer to the Arctic by the Atlantic Water layer during the last 2000 years and reconstructions from the Subpolar North Atlantic suggest a role of ocean circulation in the transition between the Medieval Climate Anomaly and the Little Ice Age. Here we explore a small ensemble of last millennium simulations, carried out with the Max Planck Institute Earth System Model, and analyze mechanisms connecting the AMOC and gyre circulation and their relation to external forcing. Our results support the important role of the Subpolar Gyre strength and the related meridional mass and temperature fluxes. We find that the modulation of the northward heat transport into the Nordic Seas and the Arctic has pronounced impact on sea-ice distribution, ocean-atmosphere interaction, and the surface climate in Scandinavia and Western Europe.

  13. Coherent Multidecadal Atmospheric and Oceanic Variability in the North Atlantic: Blocking Corresponds with Warm Subpolar Ocean

    Science.gov (United States)

    Hakkinen, Sirpa M.; Rhines, P. B.; Worthen, D. L.

    2012-01-01

    Winters with frequent atmospheric blocking, in a band of latitudes from Greenland to Western Europe, are found to persist over several decades and correspond to a warm North Atlantic Ocean. This is evident in atmospheric reanalysis data, both modern and for the full 20th century. Blocking is approximately in phase with Atlantic multidecadal ocean variability (AMV). Wintertime atmospheric blocking involves a highly distorted jetstream, isolating large regions of air from the westerly circulation. It influences the ocean through windstress-curl and associated air/sea heat flux. While blocking is a relatively high-frequency phenomenon, it is strongly modulated over decadal timescales. The blocked regime (weaker ocean gyres, weaker air-sea heat flux, paradoxically increased transport of warm subtropical waters poleward) contributes to the warm phase of AMV. Atmospheric blocking better describes the early 20thC warming and 1996-2010 warm period than does the NAO index. It has roots in the hemispheric circulation and jet stream dynamics. Subpolar Atlantic variability covaries with distant AMOC fields: both these connections may express the global influence of the subpolar North Atlantic ocean on the global climate system.

  14. Fishery intensification in small water bodies: a review for North America

    National Research Council Canada - National Science Library

    Moehl, John Frederic; Davies, William D

    1993-01-01

    .... Intensification is also achieved by enhancing water fertility through liming and fertilization. Case studies are presented representing contrasting climatic regions of North America while demonstrating similarities in management style...

  15. Particulate barium tracing of significant mesopelagic carbon remineralisation in the North Atlantic

    Science.gov (United States)

    Lemaitre, Nolwenn; Planquette, Hélène; Planchon, Frédéric; Sarthou, Géraldine; Jacquet, Stéphanie; García-Ibáñez, Maribel I.; Gourain, Arthur; Cheize, Marie; Monin, Laurence; André, Luc; Laha, Priya; Terryn, Herman; Dehairs, Frank

    2018-04-01

    The remineralisation of sinking particles by prokaryotic heterotrophic activity is important for controlling oceanic carbon sequestration. Here, we report mesopelagic particulate organic carbon (POC) remineralisation fluxes in the North Atlantic along the GEOTRACES-GA01 section (GEOVIDE cruise; May-June 2014) using the particulate biogenic barium (excess barium; Baxs) proxy. Important mesopelagic (100-1000 m) Baxs differences were observed along the transect depending on the intensity of past blooms, the phytoplankton community structure, and the physical forcing, including downwelling. The subpolar province was characterized by the highest mesopelagic Baxs content (up to 727 pmol L-1), which was attributed to an intense bloom averaging 6 mg chl a m-3 between January and June 2014 and by an intense 1500 m deep convection in the central Labrador Sea during the winter preceding the sampling. This downwelling could have promoted a deepening of the prokaryotic heterotrophic activity, increasing the Baxs content. In comparison, the temperate province, characterized by the lowest Baxs content (391 pmol L-1), was sampled during the bloom period and phytoplankton appear to be dominated by small and calcifying species, such as coccolithophorids. The Baxs content, related to oxygen consumption, was converted into a remineralisation flux using an updated relationship, proposed for the first time in the North Atlantic. The estimated fluxes were of the same order of magnitude as other fluxes obtained using independent methods (moored sediment traps, incubations) in the North Atlantic. Interestingly, in the subpolar and subtropical provinces, mesopelagic POC remineralisation fluxes (up to 13 and 4.6 mmol C m-2 d-1, respectively) were equalling and occasionally even exceeding upper-ocean POC export fluxes, deduced using the 234Th method. These results highlight the important impact of the mesopelagic remineralisation on the biological carbon pump of the studied area with a near

  16. Millennium scale radiocarbon variations in Eastern North Atlantic thermocline waters: 0-7000 years

    Energy Technology Data Exchange (ETDEWEB)

    Frank, N.; Tisnerat-Laborde, N.; Hatte, C. [LSCE, F-91190 Gif Sur Yvette, (France); Colin, C. [Univ Paris 11, IDES, Orsay, (France); Dottori, M.; Reverdin, G. [Univ Paris 06, LOCEAN, F-75252 Paris, (France)

    2009-07-01

    Complete text of publication follows: Deep water corals are exceptional archives of modern and past ocean circulation as combined U-series and radiocarbon dating allows to reconstruct seawater radiocarbon. Here we present thermocline water radiocarbon concentrations that have been reconstructed for the past {approx} 7000 years for the eastern north Atlantic, based on deep-water corals from Rockall Bank and Porcupine Seabight. We find that thermocline water radiocarbon values follow overall the mean atmospheric long term trend with an average offset of {Delta}{sup 14}C between intermediate water and atmosphere of -55{+-}5 per thousand until 1960 AD. Residual variations are strong ({+-}25 per thousand) over the past 7000 years and there is first evidence that those are synchronous to millennium scale climate variability. Over the past 60 years thermocline water radiocarbon values increase due to the penetration of bomb-radiocarbon into the upper intermediate ocean. Radiocarbon increases by {Delta}{sup 14}C of +95 per thousand compared to +210 per thousand for eastern North Atlantic surface waters. Moreover, bomb-radiocarbon penetration to thermocline depth occurs with a delay of {approx} 10-15 years. Based on high resolution ocean circulation models we suggest that radiocarbon changes at upper intermediate depth are today barely affected by vertical mixing and represent more likely variable advection and mixing of water masses from the Labrador Sea and the temperate Atlantic (including Mediterranean outflow water). Consequently, we assume that residual radiocarbon variations over the past 7000 years reflect millennium scale variability of the Atlantic sub-polar and sub-tropical gyres

  17. Hydroclimatology of Extreme Precipitation and Floods Originating from the North Atlantic Ocean

    Science.gov (United States)

    Nakamura, Jennifer

    This study explores seasonal patterns and structures of moisture transport pathways from the North Atlantic Ocean and the Gulf of Mexico that lead to extreme large-scale precipitation and floods over land. Storm tracks, such as the tropical cyclone tracks in the Northern Atlantic Ocean, are an example of moisture transport pathways. In the first part, North Atlantic cyclone tracks are clustered by the moments to identify common traits in genesis locations, track shapes, intensities, life spans, landfalls, seasonal patterns, and trends. The clustering results of part one show the dynamical behavior differences of tropical cyclones born in different parts of the basin. Drawing on these conclusions, in the second part, statistical track segment model is developed for simulation of tracks to improve reliability of tropical cyclone risk probabilities. Moisture transport pathways from the North Atlantic Ocean are also explored though the specific regional flood dynamics of the U.S. Midwest and the United Kingdom in part three of the dissertation. Part I. Classifying North Atlantic Tropical Cyclones Tracks by Mass Moments. A new method for classifying tropical cyclones or similar features is introduced. The cyclone track is considered as an open spatial curve, with the wind speed or power information along the curve considered as a mass attribute. The first and second moments of the resulting object are computed and then used to classify the historical tracks using standard clustering algorithms. Mass moments allow the whole track shape, length and location to be incorporated into the clustering methodology. Tropical cyclones in the North Atlantic basin are clustered with K-means by mass moments producing an optimum of six clusters with differing genesis locations, track shapes, intensities, life spans, landfalls, seasonality, and trends. Even variables that are not directly clustered show distinct separation between clusters. A trend analysis confirms recent conclusions

  18. Parasitic anemone infects the invasive ctenophore Mnemiopsis leidyi in the North East Atlantic

    DEFF Research Database (Denmark)

    Selander, Erik; Møller, Lene Friis; Sundberg, Per

    2010-01-01

    We report of the first finding of parasitic sea anemone larvae infecting the invasive ctenophore Mnemiopsis leidyi in the North East Atlantic. Parasitic anemone larvae are common in the native habitat of Mnemiopsis, but have not previously been reported from any of the locations where Mnemiopsis ...

  19. Cold-water fishes and climate change in North America

    Science.gov (United States)

    J. E. Williams; Daniel Isaak; J. Imhof; D. A. Hendrickson; J. R. McMillan

    2015-01-01

    Trout, salmon, grayling and whitefishes (Salmonidae) are among the most ecologically and economically important fishes. They also are among the most vulnerable to global warming, and increasing drought, floods, and wildfires. In North America, salmonids occur from central Mexico northward along coastal regions and mountainous interiors to the Arctic Plains. A...

  20. Exploring the origins of ecological forestry in North America

    Science.gov (United States)

    Anthony W. ​D' Amato; Brian J. Palik; Jerry F. Franklin; David R. Foster

    2016-01-01

    The use of ecological forestry to achieve management objectives, such as the maintenance of native biodiversity, has become increasingly common on public and private ownerships in North America. These approaches generally use natural disturbance processes and their structural and compositional outcomes as models for designing silvicultural prescriptions that restore or...

  1. Historic Storminess Changes in North Atlantic Region

    Science.gov (United States)

    Dawson, A. G.; Elliott, L.; Noone, S.; Hickey, K.; Foster, I.; Wadhams, P.; Mayewski, P.

    2001-05-01

    Reconstructed patterns of historic storminess (1870-1990 AD) for North Atlantic region as indicated by measurements from selected stations in Iceland, Faeroes, Scotland and Ireland show clear links with the climate "seesaw" winters first described by Van Loon and Rogers. The stormiest winters appear to have occurred during periods when measured Greenland air temperatures at Jacobshavn and reconstructed air temperatures from the Summit ice core site have been exceptionally low and when air temperature across northern Europe have been well above average. Maxima and minima of recorded winter storms for the various stations are also in agreement with the Sodium chronology from GISP2 that points to increased sea salt precipitation on Greenland ice at Summit during Greenland "below" periods of the climate seesaw.

  2. Lithospheric expression of geological units in central and eastern North America from full waveform tomography

    Science.gov (United States)

    Yuan, Huaiyu; French, Scott; Cupillard, Paul; Romanowicz, Barbara

    2014-09-01

    The EarthScope TA deployment has provided dense array coverage throughout the continental US and with it, the opportunity for high resolution 3D seismic velocity imaging of both lithosphere and asthenosphere in the continent. Building upon our previous long-period waveform tomographic modeling in North America, we present a higher resolution 3D isotropic and radially anisotropic shear wave velocity model of the North American lithospheric mantle, constructed tomographically using the spectral element method for wavefield computations and waveform data down to 40 s period. The new model exhibits pronounced spatial correlation between lateral variations in seismic velocity and anisotropy and major tectonic units as defined from surface geology. In the center of the continent, the North American craton exhibits uniformly thick lithosphere down to 200-250 km, while major tectonic sutures of Proterozoic age visible in the surface geology extend down to 100-150 km as relatively narrow zones of distinct radial anisotropy, with Vsv >Vsh. Notably, the upper mantle low velocity zone is present everywhere under the craton between 200 and 300 km depth. East of the continental rift margin, the lithosphere is broken up into a series of large, somewhat thinner (150 km) high velocity blocks, which extend laterally 200-300 km offshore into the Atlantic Ocean. Between the craton and these deep-rooted blocks, we find a prominent narrow band of low velocities that roughly follows the southern and eastern Laurentia rift margin and extends into New England. We suggest that the lithosphere along this band of low velocities may be thinned due to the combined effects of repeated rifting processes and northward extension of the hotspot related Bermuda low-velocity channel across the New England region. We propose that the deep rooted high velocity blocks east of the Laurentia margin represent the Proterozoic Gondwanian terranes of pan-African affinity, which were captured during the Rodinia

  3. The influence of the North Atlantic Ocean variability on the atmosphere in the cold season at seasonal to multidecadal time scales

    Science.gov (United States)

    Frankignoul, C.

    2017-12-01

    Observational evidence of an atmospheric response to the North Atlantic horseshoe SST anomalies has been accumulating since the late 90's, suggesting that it drives a negative NAO response during late fall/early winter. The North Atlantic horseshoe SST anomaly is in part stochastically driven by the atmosphere, but at low frequency it is correlated with the Atlantic Multidecadal Oscillation (AMO). Correspondingly, an atmospheric response to the AMO has been detected at low frequency in winter, with a positive AMO phase leading a negative NAO-like pattern, consistent with sensitivity studies with atmospheric general circulation models. Both the subpolar and tropical components of the AMO seem to contribute to its influence on the atmosphere. As North Atlantic SST changes reflects internally-generated SST fluctuations as well the response to anthropogenic and other external forcing, the AMO is sensitive to the way the forced SST signal is removed; estimates of the natural variability of the AMO vary by as much as a factor of two between estimation methods, leading to possible biases in its alleged impacts. Since an intensification of the Atlantic meridional overturning circulation (AMOC) leads the AMO and drives a negative NAO in many climate models, albeit with different lead times, the relation between AMO and AMOC will be discussed, as well as possible links with the North Pacific and sea ice variability.

  4. The bentonite industry in North America

    International Nuclear Information System (INIS)

    Dixon, D.A.; Hnatiw, D.S.J.; Walker, B.T.

    1992-11-01

    The Canadian Nuclear Fuel Waste Management Program is studying a concept for the disposal of nuclear fuel waste at a depth of 500 to 1000 m below the surface in stable crystalline rock of the Canadian Shield. The waste containers would be surrounded by a clay-based buffer material, composed of equal proportions of bentonite clay and silica sand. In the reference disposal concept, some 1.9 x 10 5 Mg of used fuel would be emplaced. This would require 2.5 x 10 6 Mg of bentonite. A review of the bentonite industry in North America was carried out to establish the availability of sufficient high-quality material. There are proven reserves of sodium bentonite clay in excess of 1.5 x 10 8 Mg, and vast supplies are known to exist but not yet proven. The Canadian conceptual disposal vault would require 6 x 10 4 Mg of sodium bentonite each year for 40 years. The bentonite industry of North America has an installed annual production capacity of 2 x 10 7 Mg. A disposal vault would therefore require approximately 2% of the industry capacity. A number of commercial products have been screened for potential suitability for use as a component of the buffer. Ten currently marketed bentonite products have been identified as meeting the initial quality standards for the buffer, and two non-commercial bentonites have been identified as having the potential for use in a disposal vault. (Author) (14 figs., 7 tabs., 18 refs.)

  5. Atlantic Region

    NARCIS (Netherlands)

    Elands, B.H.M.; Bell, S.; Blok, J.

    2010-01-01

    Chapter 2 explores recreation and tourism practices in forest areas in the Atlantic region, which refers to the geographical area close to the North Sea and the Atlantic Ocean. The Atlantic countries described in this section are Belgium (Flanders and Wallonia), Denmark, Iceland, Ireland, the

  6. Organic carbon budget for the eastern boundary of the North Atlantic subtropical gyre: major role of DOC in mesopelagic respiration.

    Science.gov (United States)

    Santana-Falcón, Yeray; Álvarez-Salgado, Xosé Antón; Pérez-Hernández, María Dolores; Hernández-Guerra, Alonso; Mason, Evan; Arístegui, Javier

    2017-08-31

    Transports of suspended particulate (POC susp ) and dissolved (DOC) organic carbon are inferred from a box-model covering the eastern boundary of the North Atlantic subtropical gyre. Corresponding net respiration rates (R) are obtained from a net organic carbon budget that is based on the transport estimates, and includes both vertical and lateral fluxes. The overall R in the mesopelagic layer (100-1500 m) is 1.6 ± 0.4 mmol C m -2 d -1 . DOC accounts for up to 53% of R as a result of drawdown of organic carbon within Eastern North Atlantic Central Water (ENACW) that is entrained into sinking Mediterranean Overflow Water (MOW) that leads to formation of Mediterranean water (MW) at intermediate depths (~900 m). DOC represents 90% of the respired non-sinking organic carbon. When converted into oxygen units, the computed net respiration rate represents less than half the oxygen utilization rates (OUR) reported for the mesopelagic waters of the subtropical North Atlantic. Mesoscale processes in the area, not quantified with our approach, could account in part for the OUR differences observed between our carbon budget and other published studies from the North Atlantic, although seasonal or interannual variability could also be responsible for the difference in the estimates.

  7. Catalogue of Geadephaga (Coleoptera: Adephaga of America, north of Mexico

    Directory of Open Access Journals (Sweden)

    Yves Bousquet

    2012-11-01

    Full Text Available All scientific names of Trachypachidae, Rhysodidae, and Carabidae (including cicindelines recorded from America north of Mexico are catalogued. Available species-group names are listed in their original combinations with the author(s, year of publication, page citation, type locality, location of the name-bearing type, and etymology for many patronymic names. In addition, the reference in which a given species-group name is first synonymized is recorded for invalid taxa. Genus-group names are listed with the author(s, year of publication, page citation, type species with way of fixation, and etymology for most. The reference in which a given genus-group name is first synonymized is recorded for many invalid taxa. Family-group names are listed with the author(s, year of publication, page citation, and type genus. The geographical distribution of all species-group taxa is briefly summarized and their state and province records are indicated.One new genus-group taxon, Randallius new subgenus (type species: Chlaenius purpuricollis Randall, 1838, one new replacement name, Pterostichus amadeus new name for Pterostichus vexatus Bousquet, 1985, and three changes in precedence, Ellipsoptera rubicunda (Harris, 1911 for Ellipsoptera marutha (Dow, 1911, Badister micans LeConte, 1844 for Badister ocularis Casey, 1920, and Agonum deplanatum Ménétriés, 1843 for Agonum fallianum (Leng, 1919, are proposed. Five new genus-group synonymies and 65 new species-group synonymies, one new species-group status, and 12 new combinations (see Appendix 5 are established.The work also includes a discussion of the notable private North American carabid collections, a synopsis of all extant world geadephagan tribes and subfamilies, a brief faunistic assessment of the fauna, a list of valid species-group taxa, a list of North American fossil Geadephaga (Appendix 1, a list of North American Geadephaga larvae described or illustrated (Appendix 2, a list of Geadephaga species

  8. The Dorstenia species (Moraceae) of north-western tropical America

    NARCIS (Netherlands)

    Berg, C.C.; Leeuwen, van R.W.J.

    1982-01-01

    Four new species of Dorstenia are described: D. panamensis C.C. Berg, D. boliviana C.C. Berg, D. peruviana C.C. Berg, and D. belizensis C.C. Berg. A list of and a key to the 21 Dorstenia species distinguished in north-western tropical America are presented, together with synonyms and distributions.

  9. TRACEing Last Glacial Period (25-80 ka b2k) tephra horizons within North Atlantic marine cores and exploring links to the Greenland ice-cores

    Science.gov (United States)

    Abbott, P. M.; Davies, S. M.; Griggs, A. J.; Bourne, A. J.; Cook, E.; Pearce, N. J. G.; Austin, W. E. N.; Chapman, M.; Hall, I. R.; Purcell, C. S.; Scourse, J. D.; Rasmussen, T. L.

    2015-12-01

    Tephrochronology is a powerful technique for the correlation and synchronisation of disparate palaeoclimatic records from different depositional environments and has considerable potential for testing climatic phasing. For example, the relative timing of atmospheric and marine changes caused by the abrupt climatic events that punctuated the last glacial period within the North Atlantic region. Here we report on efforts to establish a framework of tephra horizons within North Atlantic marine sequences that can correlate these records and if traced in the Greenland ice-cores can act as isochronous tie-lines. Investigations have been conducted on a network of marine cores from a number of sites across the North Atlantic. Tephra horizons have been identified using cryptotephra extraction techniques more commonly applied to the study of terrestrial sequences. There are two main challenges with assessing cryptotephras in the glacial North Atlantic; i) determining the transportation processes and ii) assessing the influence of secondary reworking processes and the stratigraphic integrity of the isochrons. These processes and their influence are investigated for each cryptotephra using shard size variations, major element heterogeneity and co-variance of IRD input for some cores. Numerous Icelandic cryptophras have been successfully identified in the marine records and we will discuss the integration of a number of these with an isochronous nature into a marine tephra framework and how potential correlations to the Greenland ice-core tephra framework are determined. Spatial patterns in the nature of tephra records that are emerging from the core network will be highlighted to outline some of the key areas that could be explored in the future. In addition, the synchronisation of multiple North Atlantic records to the Greenland ice-cores using the North Atlantic Ash Zone II to test the synchroneity of an abrupt cooling in the North Atlantic will be discussed.

  10. North Atlantic Energy Structures

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, S. [North Atlantic Energy Structures Inc., St. John' s, NL (Canada); Derradji, A. [National Research Council of Canada, St. John' s, NL (Canada). Inst. for Ocean Technology

    2005-07-01

    North Atlantic Energy Structures Inc. is in the process of designing a tidal fence for a site near the Straits of Belle Isle. This presentation provided details of both the design and the location in which the wave energy plant will be installed. Design constraints included a short seasonal work window, and a harsh but pristine environment. Design specifications of the paddlewheels and caissons were presented. The paddlewheel is iceberg and slab ice resistant, and has portals below the wheel axis, a water-free upper chamber, and bi-directional power generation. The planned installation sequence was presented, as well as details of a hydrodynamic simulation examining torque on the turbines in the tidal energy chamber. Results of the study indicated that 20 paddlewheels per caisson provided the equivalent of 12 MW of energy. A tidal fence of 70 to 80 caissons provided the equivalent of 1.2 GW of energy. A slab ice simulation study was outlined, and details of the pumping station, inlet and hydro-generation station were provided. A map of the proposed siting of the tidal fence was presented. It was concluded that financing for the pilot project has been granted. However, further financing for research and development is required. refs., tabs., figs.

  11. Icacinaceae from the eocene of Western North America.

    Science.gov (United States)

    Allen, Sarah E; Stull, Gregory W; Manchester, Steven R

    2015-05-01

    The Icacinaceae are a pantropical family of trees, shrubs, and climbers with an extensive Paleogene fossil record. Our improved understanding of phylogenetic relationships within the family provides an excellent context for investigating new fossil fruit and leaf material from the Eocene of western North America. We examined fossils from early and middle Eocene sediments of western Wyoming, northeastern Utah, northwestern Colorado, and Oregon and compared them with extant species of Iodes and other icacinaceous genera as well as previously described fossils of the family. Three new fossil species are described, including two based on endocarps (Iodes occidentalis sp. nov. and Icacinicaryites lottii sp. nov.) and one based on leaves (Goweria bluerimensis sp. nov.). The co-occurrence of I. occidentalis and G. bluerimensis suggests these might represent detached organs of a single species. A new genus, Biceratocarpum, is also established for morphologically distinct fossil fruits of Icacinaceae previously placed in Carpolithus. Biceratocarpum brownii gen. et comb. nov. resembles the London Clay species "Iodes" corniculata in possessing a pair of subapical protrusions. These fossils increase our knowledge of Icacinaceae in the Paleogene of North America and highlight the importance of the Northern Hemisphere in the early diversification of the family. They also document interchange with the Eocene flora of Europe and biogeographic connections with modern floras of Africa and Asia, where Icacinaceae are diverse today. The present-day restriction of this family to tropical regions offers ecological implications for the Eocene floras in which they occur. © 2015 Botanical Society of America, Inc.

  12. Vertical density gradient in the eastern North Atlantic during the last 30,000 years

    Energy Technology Data Exchange (ETDEWEB)

    Rogerson, M.; Ramirez, J. [University of Hull, Geography Department, Hull (United Kingdom); Bigg, G.R. [University of Sheffield, Department of Geography, Sheffield (United Kingdom); Rohling, E.J. [University of Southampton, National Oceanography Centre, School of Ocean and Earth Science, Southampton (United Kingdom)

    2012-08-15

    Past changes in the density and momentum structure of oceanic circulation are an important aspect of changes in the Atlantic Meridional Overturning Circulation and consequently climate. However, very little is known about past changes in the vertical density structure of the ocean, even very extensively studied systems such as the North Atlantic. Here we exploit the physical controls on the settling depth of the dense Mediterranean water plume derived from the Strait of Gibraltar to obtain the first robust, observations-based, probabilistic reconstruction of the vertical density gradient in the eastern North Atlantic during the last 30,000 years. We find that this gradient was weakened by more than 50%, relative to the present, during the last Glacial Maximum, and that changes in general are associated with reductions in AMOC intensity. However, we find only a small change during Heinrich Event 1 relative to the Last Glacial Maximum, despite strong evidence that overturning was substantially altered. This implies that millennial-scale changes may not be reflected in vertical density structure of the ocean, which may be limited to responses on an ocean-overturning timescale or longer. Regardless, our novel reconstruction of Atlantic density structure can be used as the basis for a dynamical measure for validation of model-based AMOC reconstructions. In addition, our general approach is transferrable to other marginal sea outflow plumes, to provide estimates of oceanic vertical density gradients in other locations. (orig.)

  13. Radium-226 and barium as tracers of water masses in the North Atlantic (GA01-GEOTRACES)

    Science.gov (United States)

    Le Roy, Emilie; Sanial, Virginie; Charette, Matthew; Henderson, Paul; Jacquet, Stéphanie; García-Ibáñez, Maribel; Pérez, Fiz; Lherminer, Pascale; Souhaut, Marc; Jeandel, Catherine; Lacan, François; van Beek, Pieter

    2017-04-01

    In this study, we report concentrations of radium-226 (226Ra, t1/2=1602 y) and barium determined along the GEOVIDE section conducted in the North Atlantic (May-July 2014; Portugal-Greenland-Canda) in the framework of the international GEOTRACES program. A high vertical resolution (up to 22 depths per station) was achieved by analyzing small volumes (˜10 L) of seawater for 226Ra using a radon emanation technique. We will present the distribution of 226Ra activities and barium concentrations in contrasting biogeochemical regions of the North Atlantic (Iberian margin, West European Basin, Reykjanes Ridge, Irminger Sea, Greenland margin and Labrador Sea). These regions strongly differ in terms of boundary inputs, biogeochemistry and deep water formation. We observe a linear correlation between 226Ra and barium along the GEOVIDE section, which results from the dominantly conservative behavior of the two tracers. However, deviations from the linear correlation between 226Ra and Ba are found in several places. The potential causes for such deviations are investigated. Optimum multi-parameter (OMP) analysis was thus used to distinguish the relative importance of physical transport (i.e., water mass mixing) from non-conservative processes (sedimentary, river or hydrothermal inputs; uptake by particles) on the 226Ra and Ba distribution in the North Atlantic.

  14. Astronomically paced changes in deep-water circulation in the western North Atlantic during the middle Eocene

    Science.gov (United States)

    Vahlenkamp, Maximilian; Niezgodzki, Igor; De Vleeschouwer, David; Bickert, Torsten; Harper, Dustin; Kirtland Turner, Sandra; Lohmann, Gerrit; Sexton, Philip; Zachos, James; Pälike, Heiko

    2018-02-01

    North Atlantic Deep Water (NADW) currently redistributes heat and salt between Earth's ocean basins, and plays a vital role in the ocean-atmosphere CO2 exchange. Despite its crucial role in today's climate system, vigorous debate remains as to when deep-water formation in the North Atlantic started. Here, we present datasets from carbonate-rich middle Eocene sediments from the Newfoundland Ridge, revealing a unique archive of paleoceanographic change from the progressively cooling climate of the middle Eocene. Well-defined lithologic alternations between calcareous ooze and clay-rich intervals occur at the ∼41-kyr beat of axial obliquity. Hence, we identify obliquity as the driver of middle Eocene (43.5-46 Ma) Northern Component Water (NCW, the predecessor of modern NADW) variability. High-resolution benthic foraminiferal δ18O and δ13C suggest that obliquity minima correspond to cold, nutrient-depleted, western North Atlantic deep waters. We thus link stronger NCW formation with obliquity minima. In contrast, during obliquity maxima, Deep Western Boundary Currents were weaker and warmer, while abyssal nutrients were more abundant. These aspects reflect a more sluggish NCW formation. This obliquity-paced paleoceanographic regime is in excellent agreement with results from an Earth system model, in which obliquity minima configurations enhance NCW formation.

  15. North Atlantic cyclones; trends, impacts and links to large-scale variability

    Science.gov (United States)

    Trigo, R. M.; Trigo, I. F.; Ramos, A. M.; Paredes, D.; Garcia-Herrera, R.; Liberato, M. L. R.; Valente, M. A.

    2009-04-01

    Based on the cyclone detection and tracking algorithm previously developed (Trigo, 2006) we have assessed the inter-annual variability and cyclone frequency trends between 1960 and 2000 for the Euro-Atlantic sector using the highest spatial resolution available (1.125° x 1.125°) from the ERA-40 Surface Level Pressure. Additionally, trends for the u and v wind speed components are also computed at the monthly and seasonal scales, using the same dataset. All cyclone and wind speed trend maps were computed with the corresponding statistical significance field. Results reveal a significant frequency decrease (increase) in the western Mediterranean (Greenland and Scandinavia), particularly in December, February and March. Seasonal and monthly analysis of wind speed trends shows similar spatial patterns. We show that these changes in the frequency of low pressure centers and the associated wind patterns are partially responsible for trends of the significant height of waves. Throughout the extended winter months (ONDJFM), regions with positive (negative) wind magnitude trends, of up to 5 cm/s per year, often correspond to regions of positive (negative) significant wave height trends. The cyclone and wind speed trends computed for the JFM months are well matched by the corresponding trends in significant wave height, with February being the month with the highest trends (negative south of 50°N up to -3 cm/year, and positive up to 5cm/year just north of Scotland). Using precipitation data from ECMWF reanalyses and a CRU high resolution dataset we show the impact of these trends in cyclone frequencies upon the corresponding precipitation trends in the influenced areas. It is also shown that these changes are partially linked to major shifts on the indices of large-scale patterns modes, namely the North Atlantic Oscillation (NAO), the Eastern Atlantic (EA) and the Scandinavian Patterns (SCAN). Trigo, I. F. 2006: Climatology and Interannual Variability of Storm-Tracks in

  16. Ungulate predation and ecological roles of wolves and coyotes in eastern North America.

    Science.gov (United States)

    Benson, John F; Loveless, Karen M; Rutledge, Linda Y; Patterson, Brent R

    2017-04-01

    Understanding the ecological roles of species that influence ecosystem processes is a central goal of ecology and conservation biology. Eastern coyotes (Canis latrans) have ascended to the role of apex predator across much of eastern North America since the extirpation of wolves (Canis spp.) and there has been considerable confusion regarding their ability to prey on ungulates and their ecological niche relative to wolves. Eastern wolves (C. lycaon) are thought to have been the historical top predator in eastern deciduous forests and have previously been characterized as deer specialists that are inefficient predators of moose because of their smaller size relative to gray wolves (C. lupus). We investigated intrinsic and extrinsic influences on per capita kill rates of white-tailed deer (Odocoileus virginianus) and moose (Alces alces) during winter by sympatric packs of eastern coyotes, eastern wolves, and admixed canids in Ontario, Canada to clarify the predatory ability and ecological roles of the different canid top predators of eastern North America. Eastern coyote ancestry within packs negatively influenced per capita total ungulate (deer and moose combined) and moose kill rates. Furthermore, canids in packs dominated by eastern coyote ancestry consumed significantly less ungulate biomass and more anthropogenic food than packs dominated by wolf ancestry. Similar to gray wolves in previous studies, eastern wolves preyed on deer where they were available. However, in areas were deer were scarce, eastern wolves killed moose at rates similar to those previously documented for gray wolves at comparable moose densities across North America. Eastern coyotes are effective deer predators, but their dietary flexibility and low kill rates on moose suggest they have not replaced the ecological role of wolves in eastern North America. © 2017 by the Ecological Society of America.

  17. [Book review] Ducks, geese and swans of North America

    Science.gov (United States)

    Krapu, Gary L.

    1983-01-01

    This is the 3rd edition of the classic work "The Ducks, Geese and Swans of North America," which was first published in December 1942.  The original edition was authored by Francis C. Kortright with color plates by T. M. Shortt. An authoritative reference on North American waterfowl for many years, the book had become outdated as a result of major advances in the field of waterfowl biology. The need to update the 1st edition culminated in the publication in 1976 of a 2nd edition authored by Frank Bellrose. Readers interested in comparing features of the 1976 edition with other major recent works on North American waterfowl by P. A. Johnsgard and R. S. Palmer should read Weller (1977, Auk 94: 173).

  18. Security Inequalities in North America: Reassessing Regional Security Complex Theory

    Directory of Open Access Journals (Sweden)

    Richard Kilroy

    2017-12-01

    Full Text Available This article re-evaluates earlier work done by the authors on Regional Security Complex Theory (RSCT in North America, using sectoral analysis initially developed by Buzan and Waever, but also adding the variables of institutions, identity, and interests. These variables are assessed qualitatively in the contemporary context on how they currently impress upon the process of securitization within sectoral relations between Canada, Mexico, and the United States. The article reviews the movement from bilateral security relations between these states to the development of a trilateral response to regional security challenges post- 9/11. It further addresses the present period and what appears to be a security process derailed by recent political changes and security inequalities, heightened by the election of Donald Trump in 2016. The article argues that while these three states initially evinced a convergence of regional security interests after 9/11, which did create new institutional responses, under the current conditions, divergence in political interests and security inequalities have reduced the explanatory power of RSCT in North America. Relations between states in North American are becoming less characterized by the role of institutions and interests and more by identity politics in the region.

  19. Tropical Cyclone Exposure for U.S. waters within the North Atlantic Ocean basin, 1900-2013

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent modeled, historical exposure of U.S. offshore and coastal waters to tropical cyclone activity within the North Atlantic Ocean basin. BOEM Outer...

  20. Systematics, Phylogeny, and Distribution of Acer (maples) in the Cenozoic of Western North America

    OpenAIRE

    Wolfe, Jack A.; Tanai, Toshimasa

    1987-01-01

    The known fossil fruits and leaves of Acer from western North America represent 91 species and 28 sections, 12 of which are extinct and are described as new sections of Acer. Sixty-four species are described as new, 2 new combinations are proposed, and 6 species are left unnamed; 21 have been previously described. The most diverse sections of Acer in the Tertiary of western North America are the extinct Glabroidea (at least 13 species), Negundo (9 species), Macrophylla (8 species), and Erioca...

  1. Range expansion by Passer montanus in North America

    Science.gov (United States)

    Burnett, J.L.; Roberts, C.P.; Allen, Craig R.; Brown, M.B.; Moulton, M.P.

    2017-01-01

    Passer montanus became established in a small area of central North America following its introduction in 1870. P. montanus underwent minimal range expansion in the first 100 years following introduction. However, the North American population of P. montanus is now growing in size and expanding in geographic distribution, having expanded approximately 125 km to the north by 1970. We quantify the distance of spread by P. montanus from its introduction site in the greater St. Louis, Missouri-Illinois, USA area, using distributional (presence) data from the National Audubon Society Christmas Bird Count surveys for the period of 1951 to 2014. Linear regressions of the average annual range center of P. montanus confirmed significant shifts to the north at a rate of 3.3 km/year (P Linear regressions of the linear and angular distance of range center indicates significant northern movement (change in angle of mean range center; P < 0.001) since 1951. Our results quantify the extent of a northward range expansion, and suggesting a probable spread of this species northward.

  2. Connectivity between surface and deep waters determines prokaryotic diversity in the North Atlantic Deep Water

    NARCIS (Netherlands)

    Frank, A.H.; Garcia, J.A.L.; Herndl, G.; Reinthaler, T.

    2016-01-01

    To decipher the influence of depth stratification andsurface provincialism on the dark ocean prokaryoticcommunity composition, we sampled the major deepwatermasses in the eastern North Atlantic coveringthree biogeographic provinces. Their diversity wasevaluated using ordination and canonical

  3. Surface electric fields for North America during historical geomagnetic storms

    Science.gov (United States)

    Wei, Lisa H.; Homeier, Nichole; Gannon, Jennifer L.

    2013-01-01

    To better understand the impact of geomagnetic disturbances on the electric grid, we recreate surface electric fields from two historical geomagnetic storms—the 1989 “Quebec” storm and the 2003 “Halloween” storms. Using the Spherical Elementary Current Systems method, we interpolate sparsely distributed magnetometer data across North America. We find good agreement between the measured and interpolated data, with larger RMS deviations at higher latitudes corresponding to larger magnetic field variations. The interpolated magnetic field data are combined with surface impedances for 25 unique physiographic regions from the United States Geological Survey and literature to estimate the horizontal, orthogonal surface electric fields in 1 min time steps. The induced horizontal electric field strongly depends on the local surface impedance, resulting in surprisingly strong electric field amplitudes along the Atlantic and Gulf Coast. The relative peak electric field amplitude of each physiographic region, normalized to the value in the Interior Plains region, varies by a factor of 2 for different input magnetic field time series. The order of peak electric field amplitudes (largest to smallest), however, does not depend much on the input. These results suggest that regions at lower magnetic latitudes with high ground resistivities are also at risk from the effect of geomagnetically induced currents. The historical electric field time series are useful for estimating the flow of the induced currents through long transmission lines to study power flow and grid stability during geomagnetic disturbances.

  4. The impact of North Atlantic wind and cyclone trends on European precipitation and significant wave height in the Atlantic.

    Science.gov (United States)

    Trigo, Ricardo M; Valente, Maria A; Trigo, Isabel F; Miranda, Pedro M A; Ramos, Alexandre M; Paredes, Daniel; García-Herrera, Ricardo

    2008-12-01

    An analysis of the frequency of cyclones and surface wind velocity for the Euro-Atlantic sector is performed by means of an objective methodology. Monthly and seasonal trends of cyclones and wind speed magnitude are computed and trends between 1960 and 2000 evaluated. Results reveal a significant frequency decrease (increase) in the western Mediterranean (Greenland and Scandinavia), particularly in December, February, and March. Seasonal and monthly analysis of wind magnitude trends shows similar spatial patterns. We show that these changes in the frequency of low-pressure centers and the associated wind patterns are partially responsible for trends in the significant height of waves. Throughout the extended winter months (October-March), regions with positive (negative) wind magnitude trends, of up to 5 cm/s/year, often correspond to regions of positive (negative) significant wave height trends. The cyclone and wind speed trends computed for January-March are well matched by the corresponding trends in significant wave height, with February being the month with the highest trends (negative south of lat 50 degrees N up to -3 cm/year, and positive up to 5 cm/year just north of Scotland). Trends in European precipitation are assessed using the Climatic Research Unit data set. The results of the assessment emphasize the link with the corresponding tendencies of cyclone frequencies. Finally, it is shown that these changes are associated, to a large extent, with the preferred phases of major large-scale atmospheric circulation modes, particularly with the North Atlantic Oscillation, the eastern Atlantic pattern, and the Scandinavian pattern.

  5. Gas to Power in North America. Issues surrounding the use of natural gas in the next generation of North American power plants

    International Nuclear Information System (INIS)

    Thorn, T.

    2006-01-01

    In January 2006 a study was concluded on Gas to Power in North America. This study has been prepared for EDI and IGU and is part of the Gas to Power Project, which has been set up in view of the pivotal role power is likely to play in the development of new gas markets and the realization that it will take enormous efforts to achieve the projected growth. In this report the focus is on North America

  6. Avian Influenza Ecology in North Atlantic Sea Ducks: Not All Ducks Are Created Equal

    Science.gov (United States)

    Hall, Jeffrey S.; Russell, Robin E.; Franson, J. Christian; Soos, Catherine; Dusek, Robert J.; Allen, R. Bradford; Nashold, Sean W.; TeSlaa, Joshua L.; Jónsson, Jón Eínar; Ballard, Jennifer R.; Harms, Naomi Jane; Brown, Justin D.

    2015-01-01

    Wild waterfowl are primary reservoirs of avian influenza viruses (AIV). However the role of sea ducks in the ecology of avian influenza, and how that role differs from freshwater ducks, has not been examined. We obtained and analyzed sera from North Atlantic sea ducks and determined the seroprevalence in those populations. We also tested swab samples from North Atlantic sea ducks for the presence of AIV. We found relatively high serological prevalence (61%) in these sea duck populations but low virus prevalence (0.3%). Using these data we estimated that an antibody half-life of 141 weeks (3.2 years) would be required to attain these prevalences. These findings are much different than what is known in freshwater waterfowl and have implications for surveillance efforts, AIV in marine environments, and the roles of sea ducks and other long-lived waterfowl in avian influenza ecology. PMID:26677841

  7. Avian influenza ecology in North Atlantic sea ducks: Not all ducks are created equal

    Science.gov (United States)

    Hall, Jeffrey S.; Russell, Robin E.; Franson, J. Christian; Soos, Catherine; Dusek, Robert J.; Allen, R. Bradford; Nashold, Sean W.; Teslaa, Joshua L.; Jónsson, Jón Einar; Ballard, Jennifer R.; Harms, Naomi Jnae; Brown, Justin D.

    2015-01-01

    Wild waterfowl are primary reservoirs of avian influenza viruses (AIV). However the role of sea ducks in the ecology of avian influenza, and how that role differs from freshwater ducks, has not been examined. We obtained and analyzed sera from North Atlantic sea ducks and determined the seroprevalence in those populations. We also tested swab samples from North Atlantic sea ducks for the presence of AIV. We found relatively high serological prevalence (61%) in these sea duck populations but low virus prevalence (0.3%). Using these data we estimated that an antibody half-life of 141 weeks (3.2 years) would be required to attain these prevalences. These findings are much different than what is known in freshwater waterfowl and have implications for surveillance efforts, AIV in marine environments, and the roles of sea ducks and other long-lived waterfowl in avian influenza ecology.

  8. PARASITES OF FRESHWATER FISHES IN NORTH AMERICA: WHY SO NEGLECTED?

    Czech Academy of Sciences Publication Activity Database

    Scholz, Tomáš; Choudhury, A.

    2014-01-01

    Roč. 100, č. 1 (2014), s. 26-45 ISSN 0022-3395 R&D Projects: GA ČR GBP505/12/G112 Institutional support: RVO:60077344 Keywords : Trematode * North America * Cestoda * Acanthocephala * Digenea Subject RIV: EG - Zoology Impact factor: 1.227, year: 2014

  9. Synchrony in the snowshoe hare cycle in Northwestern North America, 1970-2012

    Science.gov (United States)

    C.J. Krebs; K. Kielland; J.P Bryant; M. O' Donoghue; F. Doyle; C. McIntyre; D. DiFolco; N. Berg; S. Carriere; R. Boonstra; S. Boutin; A. J. Kenney; D. G. Reid; K. Bodony; J. Putera; H. K. Timm; T. Burke.

    2013-01-01

    Snowshoe hares (Lepus americanus Erxleben, 1777) fluctuate in 9–10 year cycles throughout much of their North American range. Regional synchrony has been assumed to be the rule for these cycles, so that hare populations in virtually all of northwestern North America have been assumed to be in phase. We gathered qualitative and quantitative data on...

  10. The spatial distribution and evolution characteristics of North Atlantic cyclones

    Science.gov (United States)

    Dacre, H.; Gray, S.

    2009-09-01

    Mid-latitude cyclones play a large role in determining the day-to-day weather conditions in western Europe through their associated wind and precipitation patterns. Thus, their typical spatial and evolution characteristics are of great interest to meteorologists, insurance and risk management companies. In this study a feature tracking algorithm is applied to a cyclone database produced using the Hewson-method of cyclone identification, based on low-level gradients of wet-bulb potential temperature, to produce a climatology of mid-latitude cyclones. The aim of this work is to compare the cyclone track and density statistics found in this study with previous climatologies and to determine reasons for any differences. This method is found to compare well with other cyclone identification methods; the north Atlantic storm track is reproduced along with the major regions of genesis. Differences are attributed to cyclone lifetime and strength thresholds, dataset resolution and cyclone identification and tracking methods. Previous work on cyclone development has been largely limited to case studies as opposed to analysis of climatological data, and does not distinguish between the different stages of cyclone evolution. The cyclone database used in this study allows cyclone characteristics to be tracked throughout the cyclone lifecycle. This enables the evaluation of the characteristics of cyclone evolution for systems forming in different genesis regions and a calculation of the spatial distribution and evolution of these characteristics in composite cyclones. It was found that most of the cyclones that cross western Europe originate in the east Atlantic where the baroclinicity and sea surface temperature gradients are weak compared to the west Atlantic. East Atlantic cyclones also have higher low-level relative vorticity and lower mean sea level pressure at their genesis point than west Atlantic cyclones. This is consistent with the hypothesis that they are secondary

  11. Conservation of native Pacific trout diversity in Western North America

    Science.gov (United States)

    Brooke E. Penaluna; Alicia Abadía-Cardoso; Jason B. Dunham; Francisco J. García-Dé León; Robert E. Gresswell; Arturo Ruiz Luna; Eric B. Taylor; Bradley B. Shepard; Robert Al-Chokhachy; Clint C. Muhlfeld; Kevin R. Bestgen; Kevin Rogers; Marco A. Escalante; Ernest R. Keeley; Gabriel M. Temple; Jack E. Williams; Kathleen R. Matthews; Ron Pierce; Richard L. Mayden; Ryan P. Kovach; John Carlos Garza; Kurt D. Fausch

    2016-01-01

    Pacific trout Oncorhynchus spp. in western North America are strongly valued in ecological, socioeconomic, and cultural views, and have been the subject of substantial research and conservation efforts. Despite this, the understanding of their evolutionary histories, overall diversity, and challenges to their conservation is incomplete. We review...

  12. Long term changes in flooding and heavy rainfall associated with North Atlantic tropical cyclones: Roles of the North Atlantic Oscillation and El Niño-Southern Oscillation

    Science.gov (United States)

    Aryal, Yog N.; Villarini, Gabriele; Zhang, Wei; Vecchi, Gabriel A.

    2018-04-01

    The aim of this study is to examine the contribution of North Atlantic tropical cyclones (TCs) to flooding and heavy rainfall across the continental United States. Analyses highlight the spatial variability in these hazards, their temporal changes in terms of frequency and magnitude, and their connection to large-scale climate, in particular to the North Atlantic Oscillation (NAO) and El Niño-Southern Oscillation (ENSO). We use long-term stream and rain gage measurements, and our analyses are based on annual maxima (AMs) and peaks-over-threshold (POTs). TCs contribute to ∼20-30% of AMs and POTs over Florida and coastal areas of the eastern United States, and the contribution decreases as we move inland. We do not detect statistically significant trends in the magnitude or frequency of TC floods. Regarding the role of climate, NAO and ENSO do not play a large role in controlling the frequency and magnitude of TC flooding. The connection between heavy rainfall and TCs is comparable to what observed in terms of flooding. Unlike flooding, NAO plays a significant role in TC-related extreme rainfall along the U.S. East Coast, while ENSO is most strongly linked to the TC precipitation in Texas.

  13. A Bayesian modelling framework for tornado occurrences in North America.

    Science.gov (United States)

    Cheng, Vincent Y S; Arhonditsis, George B; Sills, David M L; Gough, William A; Auld, Heather

    2015-03-25

    Tornadoes represent one of nature's most hazardous phenomena that have been responsible for significant destruction and devastating fatalities. Here we present a Bayesian modelling approach for elucidating the spatiotemporal patterns of tornado activity in North America. Our analysis shows a significant increase in the Canadian Prairies and the Northern Great Plains during the summer, indicating a clear transition of tornado activity from the United States to Canada. The linkage between monthly-averaged atmospheric variables and likelihood of tornado events is characterized by distinct seasonality; the convective available potential energy is the predominant factor in the summer; vertical wind shear appears to have a strong signature primarily in the winter and secondarily in the summer; and storm relative environmental helicity is most influential in the spring. The present probabilistic mapping can be used to draw inference on the likelihood of tornado occurrence in any location in North America within a selected time period of the year.

  14. Release of Volatiles During North Atlantic Flood Basalt Volcanism and Correlation to the Paleocene-Eocene Thermal Maximum

    Science.gov (United States)

    Pedersen, J. M.; Tegner, C.; Kent, A. J.; Ulrich, T.

    2017-12-01

    The opening of the North Atlantic Ocean between Greenland and Norway during the lower Tertiary led to intense flood basalt volcanism and the emplacement of the North Atlantic Igneous Province (NAIP). The volcanism is temporally overlapping with the Paleocene-Eocene Thermal Maximum (PETM), but ash stratigraphy and geochronology suggests that the main flood basalt sequence in East Greenland postdates the PETM. Significant environmental changes during the PETM have been attributed to the release of CO2 or methane gas due to either extensive melting of hydrates at the ocean floor or as a consequence of the interaction of mantle derived magmas with carbon rich sediments.Estimates suggest that a minimum of 1.8x106 km3 of basaltic lava erupted during North Atlantic flood basalt volcanism. Based on measurements of melt inclusions from the flood basalts our preliminary calculations suggest that approximately 2300 Gt of SO2 and 600 Gt of HCl were released into the atmosphere. Calculated yearly fluxes approach 23 Mt/y SO2 and 6 Mt/y HCl. These estimates are regarded as conservative.The S released into to the atmosphere during flood basalt volcanism can form acid aerosols that absorb and reflect solar radiation, causing an effective cooling effect. The climatic effects of the release of Cl into the atmosphere are not well constrained, but may be an important factor for extinction scenarios due to destruction of the ozone layer.The climatic changes due to the release of S and Cl in these amounts, and for periods extending for hundred thousand of years, although not yet fully constrained are likely to be significant. One consequence of the North Atlantic flood basalt volcanism may have been the initiation of global cooling to end the PETM.

  15. Distribution patterns of wintering sea ducks in relation to the North Atlantic Oscillation and local environmental characteristics

    Science.gov (United States)

    Zipkin, Elise F.; Gardner, Beth; Gilbert, Andrew T.; O'Connell, Allan F.; Royle, J. Andrew; Silverman, Emily D.

    2010-01-01

    Twelve species of North American sea ducks (Tribe Mergini) winter off the eastern coast of the United States and Canada. Yet, despite their seasonal proximity to urbanized areas in this region, there is limited information on patterns of wintering sea duck habitat use. It is difficult to gather information on sea ducks because of the relative inaccessibility of their offshore locations, their high degree of mobility, and their aggregated distributions. To characterize environmental conditions that affect wintering distributions, as well as their geographic ranges, we analyzed count data on five species of sea ducks (black scoters Melanitta nigra americana, surf scoters M. perspicillata, white-winged scoters M. fusca, common eiders Somateria mollissima, and long-tailed ducks Clangula hyemalis) that were collected during the Atlantic Flyway Sea Duck Survey for ten years starting in the early 1990s. We modeled count data for each species within ten-nautical-mile linear survey segments using a zero-inflated negative binomial model that included four local-scale habitat covariates (sea surface temperature, mean bottom depth, maximum bottom slope, and a variable to indicate if the segment was in a bay or not), one broad-scale covariate (the North Atlantic Oscillation), and a temporal correlation component. Our results indicate that species distributions have strong latitudinal gradients and consistency in local habitat use. The North Atlantic Oscillation was the only environmental covariate that had a significant (but variable) effect on the expected count for all five species, suggesting that broad-scale climatic conditions may be directly or indirectly important to the distributions of wintering sea ducks. Our results provide critical information on species-habitat associations, elucidate the complicated relationship between the North Atlantic Oscillation, sea surface temperature, and local sea duck abundances, and should be useful in assessing the impacts of climate

  16. Monitoring and Mitigation Alternatives for Protection of North Atlantic Right Whales during Offshore Wind Farm Installation

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Thomas J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Halvorsen, Michele B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Matzner, Shari [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Copping, Andrea E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stavole, Jessica [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2012-09-01

    Progress report on defining and determining monitoring and mitigation measures for protecting North Atlantic Right Whales from the effects of pile driving and other activities associated with installation of offshore wind farms.

  17. The marine radiocarbon bomb pulse across the temperate North Atlantic: a compilation of Delta

    NARCIS (Netherlands)

    Scourse, J.D.; Wanamaker jr., A.D.; Weidman, C.; Heinemeier, J.; Reimer, P.J.; Butler, P.G.; Witbaard, R.; Richardson, C.A.

    2012-01-01

    Marine radiocarbon bomb-pulse time histories of annually resolved archives from temperate regions have been underexploited. We present here series of Delta C-14 excess from known-age annual increments of the long-lived bivalve mollusk Arctica islandica from 4 sites across the coastal North Atlantic

  18. Geochemistry of Slow-Growing Corals: Reconstructing Sea Surface Temperature, Salinity and the North Atlantic Oscillation

    Science.gov (United States)

    2007-06-01

    Number 8, October 1989) The island of Bermuda (64°W, 32°N) (Fig. 1.3) located in the western sub- tropical Atlantic is an excellent location for examining...lobata at Clipperton Atoll, Coral Reefv, 18, 13-27, 1999. Lough, J. M., A strategy to improve the contribution of coral data to high-resolution...to evaluate winter Sr/Ca. The island of Bermuda (64°W, 32°N) is located in the Sargasso Sea in the sub-tropical North Atlantic. This site is

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

    Science.gov (United States)

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

    2016-09-01

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

  20. North Atlantic variability and its links to European climate over the last 3000 years.

    Science.gov (United States)

    Moffa-Sánchez, Paola; Hall, Ian R

    2017-11-23

    The subpolar North Atlantic is a key location for the Earth's climate system. In the Labrador Sea, intense winter air-sea heat exchange drives the formation of deep waters and the surface circulation of warm waters around the subpolar gyre. This process therefore has the ability to modulate the oceanic northward heat transport. Recent studies reveal decadal variability in the formation of Labrador Sea Water. Yet, crucially, its longer-term history and links with European climate remain limited. Here we present new decadally resolved marine proxy reconstructions, which suggest weakened Labrador Sea Water formation and gyre strength with similar timing to the centennial cold periods recorded in terrestrial climate archives and historical records over the last 3000 years. These new data support that subpolar North Atlantic circulation changes, likely forced by increased southward flow of Arctic waters, contributed to modulating the climate of Europe with important societal impacts as revealed in European history.

  1. Response of winter North Atlantic storm track to climate change in the CNRM-CM5 simulations

    Science.gov (United States)

    Chauvin, Fabrice; Oudar, Thomas; Sanchez-Gomez, Emilia; Terray, Laurent

    2016-04-01

    Climate variability in Europe in winter is largely controlled by North Atlantic storm tracks. These are associated with transport of energy, momentum, and water vapour, between the equator and mid latitudes. Extratropical cyclones have caused severe damages over some regions in north-western Europe, since they can combine extreme precipitation and strong winds. This is why it is relevant to study the impact of climate change on the extratropical cyclones, principally on their intensity, position or lifespan. Indeed, several recent studies have focused on this subject by using atmospheric reanalysis and general circulation models (GCMs). The main conclusions from the CMIP3 simulations showed a decreasing of the total number of cyclones and a poleward shift of their tracks in response to global warming. In the recent CMIP5 exercise, the consensus is not so clear, probably due to more complex feedbacks acting in the different models. Thus, the question of changes in North Atlantic storm-tracks with warming remains open. The main goal of this work is to explore the changes in the North Atlantic storm-tracks in the past and future decades and to analyze the contributions of the different external forcings (natural and anthropogenic) versus the internal variability. On this purpose, we use the Detection and Attribution (D&A) simulations performed with the coupled model CNRM-CM5. To characterize the extratropical cyclones and their tracks, a tracking scheme based on the detection of maximum of relative vorticity at 850 hPa is conducted. We show that the coupled model fairly well reproduces the storm genesis locations as well as the tracks pathways comparing to several atmospheric reanalysis products. In the recent historical period (1950-2005), the model shows a decrease in the number of storms in the southern North-Atlantic, when all the forcings (anthropogenic and natural) are prescribed. Even if the role of internal variability is important in the last decades (the

  2. Sea Spray Aerosol Production over the North Atlantic

    Science.gov (United States)

    Bates, T. S.; Quinn, P.

    2017-12-01

    Breaking waves on the ocean surface generate air bubbles that scavenge organic matter from the surrounding seawater. When injected into the atmosphere, these bubbles burst, yielding sea spray aerosol (SSA), a mixture of organic and inorganic compounds with the organic matter enriched relative to seawater. SSA mass is well documented as the dominant component of aerosol light scattering over the remote oceans. The importance of SSA number to marine boundary layer cloud condensation nuclei (CCN) is much less certain. During the Western Atlantic Climate Study cruises (WACS-1 - August 2012 and WACS-2 - May-June 2014) and the North Atlantic Aerosols and Marine Ecosystem Study cruises (NAAMES-1 - November 2015, NAAMES-2 - May 2016, and NAAMES-3 - September 2017), we generated and measured freshly emitted SSA using the Sea Sweep SSA generator. During the 2017 cruise we also generated SSA with a Marine Aerosol Reference Tank (MART). Using the data generated on these 5 cruises and a large database of remote marine boundary layer aerosol measurements we will address three questions during this presentation: 1 - Do phytoplankton ecosystems affect the organic enrichment of freshly emitted SSA?, 2 - Do plankton ecosystems affect the number production flux of SSA?, and 3 - Is SSA a significant source of atmospheric CCN?

  3. Enhanced aridity and atmospheric high-pressure stability over the western Mediterranean during the North Atlantic cold events of the past 50 k.y.

    Science.gov (United States)

    Combourieu Nebout, N.; Turon, J. L.; Zahn, R.; Capotondi, L.; Londeix, L.; Pahnke, K.

    2002-10-01

    Multiproxy paleoenvironmental records (pollen and planktonic isotope) from Ocean Drilling Program Site 976 (Alboran Sea) document rapid ocean and climate variations during the last glacial that follow the Dansgaard-Oeschger climate oscillations seen in the Greenland ice core records, thus suggesting a close link of the Mediterranean climate swings with North Atlantic climates. Continental conditions rapidly oscillated through cold-arid and warm-wet conditions in the course of stadial-interstadial climate jumps. At the time of Heinrich events, i.e., maximum meltwater flux to the North Atlantic, western Mediterranean marine microflora and microfauna show rapid cooling correlated with increasing continental dryness. Enhanced aridity conceivably points to prolonged wintertime stability of atmospheric high-pressure systems over the southwestern Mediterranean in conjunction with cooling of the North Atlantic.

  4. Natural gas pricing and contracting practices in North America

    International Nuclear Information System (INIS)

    Hassan, F.

    1992-01-01

    Over the past 5 years the natural gas industry in North America has undergone substantial change as a result of the deregulated market. A comparison is provided of the key contract parameters in gas purchase contracts utilized by local distribution companies, industrial customers, cogenerators and marketers. Issues discussed include pricing mechanisms, indexed contracts, negotiated contracts, combinations, dispute resolution, supply, government regulation, industry structures, financial considerations, perception, geological influences, demand, transmission, storage, distribution, price trends and forecasts, Order 636 in the U.S., the evolution of North American market hubs, the futures market, and 'daisy chains' of connecting pipelines. 15 refs., 7 figs., 1 tab

  5. A phylogeographic investigation of the kelp genus Laminaria (Laminariales, Phaeophyceae), with emphasis on the South Atlantic Ocean.

    Science.gov (United States)

    Rothman, Mark D; Mattio, Lydiane; Anderson, Robert J; Bolton, John J

    2017-08-01

    The genus Laminaria has a wide distribution range compared with other kelp genera because it is found in both the North and the South Atlantic, on both sides of the North Pacific, as well as in the Mediterranean. Hypotheses behind this biogeographical pattern have been discussed by several authors but have not yet been fully evaluated with time-calibrated phylogenies. Based on the analysis of four molecular markers (ITS2, rbcL, atp8 and trnWI), our goal was to reassess the Laminaria species diversity in South Africa, assess its relationship with the other species distributed in the South Atlantic and reconstruct the historical biogeography of the genus. Our results confirm the occurrence of a single species, L. pallida, in southern Africa, and its sister relationship with the North Atlantic L. ochroleuca. Both species belonged to a clade containing the other South Atlantic species: L. abyssalis from Brazil, and the Mediterranean L. rodriguezii. Our time-calibrated phylogenies suggest that Laminaria originated in the northern Pacific around 25 mya, followed by at least two migration events through the Bering Strait after its opening (~5.32 mya). Today, the first is represented by L. solidungula in the Arctic, while the second gave rise to the rest of the Atlantic species. The colonization of the North Atlantic was followed by a gradual colonization southward along the west coast of Europe, into the Mediterranean (~2.07 mya) and two recent, but disconnected, migrations (~1.34 and 0.87 mya) across the equator, giving rise to L. abyssalis in Brazil and L. pallida in southern Africa, respectively. © 2017 Phycological Society of America.

  6. [Conservation tillage systems in North America and their significance for China].

    Science.gov (United States)

    Yang, Xueming; Zhang, Xiaoping; Fang, Huajun; Liang, Aizhen; Qi, Xiaoning; Wang, Yang

    2004-02-01

    Soil degradation through erosion and desertification reduces soil productivity, and is a serious problem in agricultural production of China. To avert our arable land from further degradation, soil management must be shifted from degrading tillage to conservation practices. Over viewing the technology used in the 20th century for controlling soil degradation from erosion, conservation tillage developed in the United States and adopted in South America and Africa is one of the most successful measures to overcome soil degradation problems. This paper reviewed the historical development and the current situation of conservation tillage systems used in North and South America, with special reference to their effects on soil erosion control and soil quality. The increasing adoption of conservation tillage systems in North and South America and Africa followed an enhanced awareness of the increasing risk of soil erosion and the high cost of fuel associated with conventional tillage. Many crucial points for successfully adopting conservation tillage systems were emphasized, such as equipment/tool development and chemical weed control. Adopting conservation tillage could provide China with low-priced means of reducing soil degradation and improving soil and water quality.

  7. Visual Analysis of North Atlantic Hurricane Trends Using Parallel Coordinates and Statistical Techniques

    National Research Council Canada - National Science Library

    Steed, Chad A; Fitzpatrick, Patrick J; Jankun-Kelly, T. J; Swan II, J. E

    2008-01-01

    ... for a particular dependent variable. These capabilities are combined into a unique visualization system that is demonstrated via a North Atlantic hurricane climate study using a systematic workflow. This research corroborates the notion that enhanced parallel coordinates coupled with statistical analysis can be used for more effective knowledge discovery and confirmation in complex, real-world data sets.

  8. A right whale pootree: classification trees of faecal hormones identify reproductive states in North Atlantic right whales (Eubalaena glacialis).

    Science.gov (United States)

    Corkeron, Peter; Rolland, Rosalind M; Hunt, Kathleen E; Kraus, Scott D

    2017-01-01

    Immunoassay of hormone metabolites extracted from faecal samples of free-ranging large whales can provide biologically relevant information on reproductive state and stress responses. North Atlantic right whales ( Eubalaena glacialis Müller 1776) are an ideal model for testing the conservation value of faecal metabolites. Almost all North Atlantic right whales are individually identified, most of the population is sighted each year, and systematic survey effort extends back to 1986. North Atlantic right whales number trees as an alternative method of analysing multiple-hormone data sets, building on univariate models that have previously been used to describe hormone profiles of individual North Atlantic right whales of known reproductive state. Our tree correctly classified the age class, sex and reproductive state of 83% of 112 faecal samples from known individual whales. Pregnant females, lactating females and both mature and immature males were classified reliably using our model. Non-reproductive [i.e. 'resting' (not pregnant and not lactating) and immature] females proved the most unreliable to distinguish. There were three individual males that, given their age, would traditionally be considered immature but that our tree classed as mature males, possibly calling for a re-evaluation of their reproductive status. Our analysis reiterates the importance of considering the reproductive state of whales when assessing the relationship between cortisol concentrations and stress. Overall, these results confirm findings from previous univariate statistical analyses, but with a more robust multivariate approach that may prove useful for the multiple-analyte data sets that are increasingly used by conservation physiologists.

  9. First records of Cyclorhipidion fukiense (Eggers) (Coleoptera: Curculionidae: Scolytinae: Xyleborini), an ambrosia beetle native to Asia, in North America.

    Science.gov (United States)

    Hoebeke, E Richard; Rabaglia, Robert J; KnÍŽek, MiloŠ; Weaver, John S

    2018-03-13

    The Asian ambrosia beetle, Cyclorhipidion fukiense (Eggers) was detected for the first time in North America based on three specimens trapped in 2012 from three localities in South Carolina and two other specimens intercepted at the port of Savannah, Georgia, in 2010. The species is characterized, illustrated with high-resolution images, and compared with two other congeneric, adventive species (C. bodoanum and C. pelliculosum) presently established in eastern North America. Morphometric measurements are provided and a provisional key is presented to the species of Cyclorhipidion occurring in North America.

  10. Chemistry and dynamics of the lower troposphere over North America and the North Atlantic Ocean in fall 1997 observed using an airborne UV DIAL system

    Science.gov (United States)

    Grant, William B.; Butler, Carolyn F.; Fenn, Marta A.; Kooi, Susan A.; Browell, Edward V.; Fuelberg, Henry

    1998-01-01

    The NASA Langley Research Center's airborne UV Differential Absorption Lidar (DIAL) system participated in the Subsonic Assessment, Ozone and Nitrogen Oxide Experiment (SONEX) mission from October 13 to November 12, 1997. The purpose of the mission was to study the upper troposphere/lower stratosphere in and near the North Atlantic flight corridor to better understand this region of the atmosphere and how civilian air travel in the corridor might be affecting the atmospheric chemistry. Bases of operations included NASA Ames, California (37.4 deg N, 122.1 deg W); Bangor, Maine (44.8 deg N, 68.8 deg W); Shannon, Ireland (52.7 deg N, 8.9 deg W); and Lajes, Terceira Island, Azores (38.8 deg N, 27.1 deg W). Since the UV DIAL system observes in the nadir as well as the zenith, aerosol and ozone data were obtained from near the Earth's surface to the lower stratosphere. A number of interesting features were noted relating to both chemistry and dynamics of the troposphere, which are reported here.

  11. Atmospheric teleconnection influence on North American land surface phenology

    Science.gov (United States)

    Dannenberg, Matthew P.; Wise, Erika K.; Janko, Mark; Hwang, Taehee; Kolby Smith, W.

    2018-03-01

    Short-term forecasts of vegetation activity are currently not well constrained due largely to our lack of understanding of coupled climate-vegetation dynamics mediated by complex interactions between atmospheric teleconnection patterns. Using ecoregion-scale estimates of North American vegetation activity inferred from remote sensing (1982-2015), we examined seasonal and spatial relationships between land surface phenology and the atmospheric components of five teleconnection patterns over the tropical Pacific, north Pacific, and north Atlantic. Using a set of regression experiments, we also tested for interactions among these teleconnection patterns and assessed predictability of vegetation activity solely based on knowledge of atmospheric teleconnection indices. Autumn-to-winter composites of the Southern Oscillation Index (SOI) were strongly correlated with start of growing season timing, especially in the Pacific Northwest. The two leading modes of north Pacific variability (the Pacific-North American, PNA, and West Pacific patterns) were significantly correlated with start of growing season timing across much of southern Canada and the upper Great Lakes. Regression models based on these Pacific teleconnections were skillful predictors of spring phenology across an east-west swath of temperate and boreal North America, between 40°N-60°N. While the North Atlantic Oscillation (NAO) was not strongly correlated with start of growing season timing on its own, we found compelling evidence of widespread NAO-SOI and NAO-PNA interaction effects. These results suggest that knowledge of atmospheric conditions over the Pacific and Atlantic Oceans increases the predictability of North American spring phenology. A more robust consideration of the complexity of the atmospheric circulation system, including interactions across multiple ocean basins, is an important step towards accurate forecasts of vegetation activity.

  12. Holocene lowering of the Laurentide ice sheet affects North Atlantic gyre circulation and climate

    Science.gov (United States)

    Ivanovic, R. F.; Gregoire, L. J.; Maycock, A.; Valdes, P. J.

    2017-12-01

    The Laurentide ice sheet, which covered Canada during glacial periods, had a major influence on atmospheric circulation and surface climate, but its role in climate during the early Holocene (9-7 ka), when it was thinner and confined around Hudson Bay, is unclear. It has been suggested that the demise of the ice sheet played a role in the 8.2 ka event (an abrupt 1-3 °C Northern Hemisphere cooling lasting 160 years) through the influence of changing topography on atmospheric circulation. To test this hypothesis, and to investigate the broader implications of changing ice sheet topography for climate, we analyse a set of equilibrium climate simulations with ice sheet topographies taken at 500 year intervals from 9.5 ka to 8.0 ka. Between 9.5 and 8.0 ka, our simulations show a 2 °C cooling south of Iceland and a 1 °C warming between 40-50° N in the North Atlantic. These surface temperature changes are associated with a weakening of the subtropical and subpolar gyres caused by a decreasing wind stress curl over the mid-North Atlantic as the ice sheet lowers. The climate response is strongest during the period of peak ice volume change (9.5 ka - 8.5 ka), but becomes negligible after 8.5 ka. The climatic effects of the Laurentide ice sheet lowering are restricted to the North Atlantic sector. Thus, topographic forcing did not play a significant role in the 8.2 ka event and had only a small effect on Holocene climate change compared to the effects of changes in greenhouse gases, insolation and ice sheet meltwater.

  13. Holocene lowering of the Laurentide ice sheet affects North Atlantic gyre circulation and climate

    Science.gov (United States)

    Gregoire, Lauren J.; Ivanovic, Ruza F.; Maycock, Amanda C.; Valdes, Paul J.; Stevenson, Samantha

    2018-02-01

    The Laurentide ice sheet, which covered Canada during glacial periods, had a major influence on atmospheric circulation and surface climate, but its role in climate during the early Holocene (9-7 ka), when it was thinner and confined around Hudson Bay, is unclear. It has been suggested that the demise of the ice sheet played a role in the 8.2 ka event (an abrupt 1-3 °C Northern Hemisphere cooling lasting 160 years) through the influence of changing topography on atmospheric circulation. To test this hypothesis, and to investigate the broader implications of changing ice sheet topography for climate, we analyse a set of equilibrium climate simulations with ice sheet topographies taken at 500 year intervals from 9.5 to 8.0 ka. Between 9.5 and 8.0 ka, our simulations show a 2 °C cooling south of Iceland and a 1 °C warming between 40° and 50°N in the North Atlantic. These surface temperature changes are associated with a weakening of the subtropical and subpolar gyres caused by a decreasing wind stress curl over the mid-North Atlantic as the ice sheet lowers. The climate response is strongest during the period of peak ice volume change (9.5-8.5 ka), but becomes negligible after 8.5 ka. The climatic effects of the Laurentide ice sheet lowering during the Holocene are restricted to the North Atlantic sector. Thus, topographic forcing is unlikely to have played a major role in the 8.2 ka event and had only a small effect on Holocene climate change compared to the effects of changes in greenhouse gases, insolation and ice sheet meltwater.

  14. Review on the Projections of Future Storminess over the North Atlantic European Region

    Directory of Open Access Journals (Sweden)

    Tina Mölter

    2016-04-01

    Full Text Available This is an overview of the results from previously published climate modeling studies reporting on projected aspects of future storminess over the North Atlantic European region (NAER in the period 2020–2190. Changes in storminess are summarized for seven subregions in the study area and rated by a categorical evaluation scheme that takes into account emission scenarios and modeling complexity in the reviewed studies. Although many of the reviewed studies reported an increase in the intensity of high-impact wind speed and extreme cyclone frequency in the second half of the 21st century, the projections of aspects of future storminess over the NAER differed regionally. There is broad consensus that the frequency and intensity of storms, cyclones, and high-impact wind speed will increase over Central and Western Europe, and these changes will probably have the potential to produce more damage. In contrast, future extratropical storminess over Southern Europe is very likely to decrease. For Northern and Eastern Europe the results of the evaluation are inconclusive, because there is an indication of increasing as well as decreasing development of the evaluated aspects of future storminess. Concerning the storm track, we found indications of a likely north- and eastward shift in most assessed studies. Results from three studies suggest a northeastward shift of the North Atlantic Oscillation.

  15. Comparison of measured and simulated wind speed data in the North Atlantic

    Energy Technology Data Exchange (ETDEWEB)

    Winterfeldt, J. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Kuestenforschung

    2008-11-06

    A systematic investigation and comparison of near-surface marine wind speed obtained from in situ and satellite observations, atmospheric reanalyses and regional atmospheric hindcasts with reanalysis driven regional climate models (RCMs) is presented for the eastern North Atlantic and the North Sea. Wind speed retrievals from two remote sensing data sets, namely QuikSCAT and the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite (HOAPS) data set, are found to give good representation of observed near-surface wind speed. The value of the root mean squared error (RMSE) for all co-located HOAPS and in situ wind speed data is 2 m/s, while it is 1.8 m/s for QuikSCAT demonstrating that QuikSCAT's mission requirement of providing wind speed with an RMSE of 2 m/s is met for the eastern North Atlantic and the North Sea. QuikSCAT shows a slightly better agreement with observed instantaneous wind speed and its frequency distribution than HOAPS. In contrast, HOAPS wind speed is available for a much longer period and is therefore the more suitable product for climatic studies or investigations of trends in wind speed. The capability of two state-of-the-art RCMs (with and without spectral nudging applied) to add value for surface marine wind fields in comparison to the reanalysis wind speed forcing is assessed by the comparison with in situ wind speed observations in the eastern North Atlantic in 1998. The comparison of the 10 m wind speed forecasts from the NCEP/NCAR and NCEP/DOE-II reanalyses with in-situ observations demonstrates the implausibility of the latter forecast resulting in its non-consideration in the added value assessment. The added value is investigated for instantaneous wind speeds (relevant for case studies) and their frequency distribution (relevant for e.g., extreme value statistics and estimations of wind potential). The observations are discriminated into groups according to their proximity to land and assimilation status, meaning whether

  16. Tectonic history of the southeastern North America

    Energy Technology Data Exchange (ETDEWEB)

    Hatcher, R.D. Jr. (Univ. of Tennessee, Knoxville, TN (United States). Dept. of Geological Sciences Oak Ridge National Lab., TN (United States))

    1993-03-01

    The present-day configuration of the crust of southeastern North America (SENA) is the product of a lengthy history traceable through more than 1 billion yr. of geologic time. The Appalachians (AP) record complete Wilson cycles of opening and closing of several oceans from ca. 690 Ma to 245 M. The final event forming the AP was the collision of SENA with Gondwana to form the supercontinent Pangaea. The Ouachitas (OA) had a somewhat different history culminating with island-arc collision during the Pennsylvanian--before the final collision began in the AP. SENA faced the open lapetos ocean no earlier than the Early Cambrian. The AP and OA were built on an earlier margin formed by rifting of the Rodonia super-continent formed by construction of the 1.2 to 1.0 Ga Grenville orogen, and farther west, a crust formed by still earlier (1.3 and 1.8 Ga) events. Recent suggestions that part of the AP platform is in Argentina raises the possibility that a fragment was rifted from between the AP and OA during the early Paleozoic. The crust beneath the Mississippi Embayment is atypical of continental crust, and would have been rifted during the Neoproterozoic and early Paleozoic. The Argentine fragment may have been removed along a transform that was reactivated several times since. Northern Pangaea was rifted during the Late Triassic and Early Jurassic and SENA once again faced open ocean-the nascent present Atlantic (AT) when spreading began. The Gulf of Mexico (GOM) also opened then forming extensive salt deposits. The AT opened partly along the old suture, but produced a failed rift in GA and FL leaving a piece of Africa forming the crust beneath the Coastal Plain as far south as central FL. The overlying sediments record recurrent uplift and decay of the AP and OA, cooling of new AT oceanic crust, eustatic sea-level changes during the Mesozoic and Cenozoic, and uplift of the Rockies providing a new source of voluminous detritus that is still being deposited in the GOM.

  17. Late Cretaceous restructuring of terrestrial communities facilitated the end-Cretaceous mass extinction in North America.

    Science.gov (United States)

    Mitchell, Jonathan S; Roopnarine, Peter D; Angielczyk, Kenneth D

    2012-11-13

    The sudden environmental catastrophe in the wake of the end-Cretaceous asteroid impact had drastic effects that rippled through animal communities. To explore how these effects may have been exacerbated by prior ecological changes, we used a food-web model to simulate the effects of primary productivity disruptions, such as those predicted to result from an asteroid impact, on ten Campanian and seven Maastrichtian terrestrial localities in North America. Our analysis documents that a shift in trophic structure between Campanian and Maastrichtian communities in North America led Maastrichtian communities to experience more secondary extinction at lower levels of primary production shutdown and possess a lower collapse threshold than Campanian communities. Of particular note is the fact that changes in dinosaur richness had a negative impact on the robustness of Maastrichtian ecosystems against environmental perturbations. Therefore, earlier ecological restructuring may have exacerbated the impact and severity of the end-Cretaceous extinction, at least in North America.

  18. The conquering of North America: dated phylogenetic and biogeographic inference of migratory behavior in bee hummingbirds.

    Science.gov (United States)

    Licona-Vera, Yuyini; Ornelas, Juan Francisco

    2017-06-05

    Geographical and temporal patterns of diversification in bee hummingbirds (Mellisugini) were assessed with respect to the evolution of migration, critical for colonization of North America. We generated a dated multilocus phylogeny of the Mellisugini based on a dense sampling using Bayesian inference, maximum-likelihood and maximum parsimony methods, and reconstructed the ancestral states of distributional areas in a Bayesian framework and migratory behavior using maximum parsimony, maximum-likelihood and re-rooting methods. All phylogenetic analyses confirmed monophyly of the Mellisugini and the inclusion of Atthis, Calothorax, Doricha, Eulidia, Mellisuga, Microstilbon, Myrmia, Tilmatura, and Thaumastura. Mellisugini consists of two clades: (1) South American species (including Tilmatura dupontii), and (2) species distributed in North and Central America and the Caribbean islands. The second clade consists of four subclades: Mexican (Calothorax, Doricha) and Caribbean (Archilochus, Calliphlox, Mellisuga) sheartails, Calypte, and Selasphorus (incl. Atthis). Coalescent-based dating places the origin of the Mellisugini in the mid-to-late Miocene, with crown ages of most subclades in the early Pliocene, and subsequent species splits in the Pleistocene. Bee hummingbirds reached western North America by the end of the Miocene and the ancestral mellisuginid (bee hummingbirds) was reconstructed as sedentary, with four independent gains of migratory behavior during the evolution of the Mellisugini. Early colonization of North America and subsequent evolution of migration best explained biogeographic and diversification patterns within the Mellisugini. The repeated evolution of long-distance migration by different lineages was critical for the colonization of North America, contributing to the radiation of bee hummingbirds. Comparative phylogeography is needed to test whether the repeated evolution of migration resulted from northward expansion of southern sedentary

  19. North Atlantic teleconnection patterns signature on sea level from satellite altimetry

    Science.gov (United States)

    Iglesias, Isabel; Lázaro, Clara; Joana Fernandes, M.; Bastos, Luísa

    2015-04-01

    Presently, satellite altimetry record is long enough to appropriately study inter-annual signals in sea level anomaly and ocean surface circulation, allowing the association of teleconnection patterns of low-frequency variability with the response of sea level. The variability of the Atlantic Ocean at basin-scale is known to be complex in space and time, with the dominant mode occurring on annual timescales. However, interannual and decadal variability have already been documented in sea surface temperature. Both modes are believed to be linked and are known to influence sea level along coastal regions. The analysis of the sea level multiannual variability is thus essential to understand the present climate and its long-term variability. While in the open-ocean sea level anomaly from satellite altimetry currently possesses centimetre-level accuracy, satellite altimetry measurements become invalid or of lower accuracy along the coast due to the invalidity of the wet tropospheric correction (WTC) derived from on-board microwave radiometers. In order to adequately analyse long-term changes in sea level in the coastal regions, satellite altimetry measurements can be recovered by using an improved WTC computed from recent algorithms that combine wet path delays from all available observations (remote sensing scanning imaging radiometers, GNSS stations, microwave radiometers on-board satellite altimetry missions and numerical weather models). In this study, a 20-year (1993-2013) time series of multi-mission satellite altimetry (TOPEX/Poseidon, Jason-1, OSTM/Jason-2, ERS-1/2, ENVISAT, CryoSat-2 and SARAL), are used to characterize the North Atlantic (NA) long-term variability on sea level at basin-scale and analyse its response to several atmospheric teleconnections known to operate on the NA. The altimetry record was generated using an improved coastal WTC computed from either the GNSS-derived path Delay or the Data Combination methodologies developed by University of

  20. High export via small particles before the onset of the North Atlantic spring bloom

    DEFF Research Database (Denmark)

    Giering, S. L. C.; Sanders, R.; Martin, A. P.

    2016-01-01

    Sinking organic matter in the North Atlantic Ocean transfers 1-3 Gt carbon yr-1 from the surface ocean to the interior. The majority of this exported material is thought to be in form of large, rapidly sinking particles that aggregate during or after the spring phytoplankton bloom. However, recent...

  1. Methane (CH4) Flux for North America L4 Daily V1 (CMS_CH4_FLX_NAD) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The CMS Methane (CH4) Flux for North America data set contains estimates of methane emission in North America based on an inversion of the GEOS-Chem chemical...

  2. Revised estimate for the radiocarbon age of North Atlantic deep water

    International Nuclear Information System (INIS)

    Broecker, W.S.

    1979-01-01

    The extent to which the admixture of water of Antarctic origin influences the 14 C/C ratio in North Atlantic deep water (NADW) has been heretofore underestimated. When this correction is properly made, a ventilation time for the deep western Atlantic is reduced to only about 100 years. The production rate of the northern component of NADW entering the western basin must be of the order of 30 Sv. If this northern component water is assumed to be the major supplier of new 14 C to the deep sea, the carbon isotope ventilation time of the world deep ocean must be of the order of 900 years. However, since the new deep waters formed around the perimeter of the Antarctic are thought to enter the deep sea at a rate of about 20 Sv, the water ventilation time for the deep sea is of the order of 550 years

  3. Distribution and protection of climatic refugia in North America.

    Science.gov (United States)

    Michalak, Julia L; Lawler, Joshua J; Roberts, David R; Carroll, Carlos

    2018-05-10

    As evidenced by past climatic refugia, locations projected to harbor remnants of present day climates may serve as critical refugia for current biodiversity in the face of modern climate change. Here, we map potential future climatic refugia across North America, defined as locations with increasingly rare climatic conditions. We identified these locations by tracking projected changes in the size and distribution of climate analogs over time. We used biologically-derived thresholds to define analogs and tested the impacts of dispersal limitation using four distances to limit analog searches. We identified at most 12% of North America as potential climatic refugia. Refugia extent varied depending on the analog threshold, dispersal distance, and climate projection. However, in all cases refugia were concentrated at high elevations and in topographically complex regions. Refugia identified using different climate projections were largely nested, suggesting that identified refugia were relatively robust to climate projection selection. Existing conservation areas cover approximately 10% of North America and yet protected up to 25% of identified refugia, indicating that protected areas disproportionately include refugia. Refugia located at lower latitudes (≤ 40°N) and slightly lower elevations (∼2500 m) were more likely to be unprotected. Based on our results, a 23% expansion of the protected areas network would be sufficient to protect the refugia that were present under all three of the climate projections that we explored. We propose that these refugia are high conservation priorities, due to their potential to harbor rare species in the future. However, these locations are simultaneously highly vulnerable to climate change over the long-term. We found that these refugia contracted substantially between the 2050s and the 2080s, emphasizing that the pace of climate change will strongly determine the availability and effectiveness of refugia for protecting today

  4. Arthropod Envenomation in North America.

    Science.gov (United States)

    Erickson, Timothy B; Cheema, Navneet

    2017-05-01

    Arthropods (phylum Arthopoda) account for a higher percentage of morbidity and mortality to humans than do mammalian bites, snake bites, or marine envenomation. They are ubiquitous in domestic dwellings, caves, and campsites and in wilderness settings such as deserts, forests, and lakes. Although arthropods are most intrusive during warmer months, many are active throughout the winter, particularly indoors. Arthropods are also nocturnal and often bite unsuspecting victims while they are sleeping. Encounters with humans are generally defensive, accidental, or reactive. An individual stung by an insect or bitten by an arachnid may experience pain and local swelling, an anaphylactic reaction, or life-threatening toxicity. This review discusses the clinical presentation and latest treatment recommendations for bites and stings from spiders, scorpions, bees, ants, ticks and centipedes of North America. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Assessing the proposed pre-last glacial maximum human occupation of North America at Coats-Hines-Litchy, Tennessee, and other sites

    Science.gov (United States)

    Tune, Jesse W.; Waters, Michael R.; Schmalle, Kayla A.; DeSantis, Larisa R. G.; Kamenov, George D.

    2018-04-01

    Genomic studies indicate that the first Pleistocene foragers who entered North America diverged from ancestral populations in Beringia sometime after the Last Glacial Maximum (LGM); however, several archaeological sites in North America have been proposed to predate the LGM. We present the results of our excavation and analysis of one such site, Coats-Hines-Litchy, Tennessee, which show that this site is a paleontological locality containing a geofact assemblage that pre-dates the LGM. Other sites in North America that purportedly predate the LGM occur in geomorphic contexts that are also conducive to the formation of geofact assemblages. As such, we propose that the reported artifacts from these sites were created by natural processes. No sites in North America currently provide credible evidence of a pre-LGM occupation.

  6. Clustering of 770,000 genomes reveals post-colonial population structure of North America

    Science.gov (United States)

    Han, Eunjung; Carbonetto, Peter; Curtis, Ross E.; Wang, Yong; Granka, Julie M.; Byrnes, Jake; Noto, Keith; Kermany, Amir R.; Myres, Natalie M.; Barber, Mathew J.; Rand, Kristin A.; Song, Shiya; Roman, Theodore; Battat, Erin; Elyashiv, Eyal; Guturu, Harendra; Hong, Eurie L.; Chahine, Kenneth G.; Ball, Catherine A.

    2017-02-01

    Despite strides in characterizing human history from genetic polymorphism data, progress in identifying genetic signatures of recent demography has been limited. Here we identify very recent fine-scale population structure in North America from a network of over 500 million genetic (identity-by-descent, IBD) connections among 770,000 genotyped individuals of US origin. We detect densely connected clusters within the network and annotate these clusters using a database of over 20 million genealogical records. Recent population patterns captured by IBD clustering include immigrants such as Scandinavians and French Canadians; groups with continental admixture such as Puerto Ricans; settlers such as the Amish and Appalachians who experienced geographic or cultural isolation; and broad historical trends, including reduced north-south gene flow. Our results yield a detailed historical portrait of North America after European settlement and support substantial genetic heterogeneity in the United States beyond that uncovered by previous studies.

  7. Emerald ash borer invasion of North America: history, biology, ecology, impacts, and management.

    Science.gov (United States)

    Herms, Daniel A; McCullough, Deborah G

    2014-01-01

    Since its accidental introduction from Asia, emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), has killed millions of ash trees in North America. As it continues to spread, it could functionally extirpate ash with devastating economic and ecological impacts. Little was known about EAB when it was first discovered in North America in 2002, but substantial advances in understanding of EAB biology, ecology, and management have occurred since. Ash species indigenous to China are generally resistant to EAB and may eventually provide resistance genes for introgression into North American species. EAB is characterized by stratified dispersal resulting from natural and human-assisted spread, and substantial effort has been devoted to the development of survey methods. Early eradication efforts were abandoned largely because of the difficulty of detecting and delineating infestations. Current management is focused on biological control, insecticide protection of high-value trees, and integrated efforts to slow ash mortality.

  8. Large bio-geographical shifts in the north-eastern Atlantic Ocean: From the subpolar gyre, via plankton, to blue whiting and pilot whales

    Science.gov (United States)

    Hátún, H.; Payne, M. R.; Beaugrand, G.; Reid, P. C.; Sandø, A. B.; Drange, H.; Hansen, B.; Jacobsen, J. A.; Bloch, D.

    2009-03-01

    Pronounced changes in fauna, extending from the English Channel in the south to the Barents Sea in the north-east and off Greenland in the north-west, have occurred in the late 1920s, the late 1960s and again in the late 1990s. We attribute these events to exchanges of subarctic and subtropical water masses in the north-eastern North Atlantic Ocean, associated with changes in the strength and extent of the subpolar gyre. These exchanges lead to variations in the influence exerted by the subarctic or Lusitanian biomes on the intermediate faunistic zone in the north-eastern Atlantic. This strong and persistent bottom-up bio-physical link is demonstrated using a numerical ocean general circulation model and data on four trophically connected levels in the food chain - phytoplankton, zooplankton, blue whiting, and pilot whales. The plankton data give a unique basin-scale depiction of these changes, and a long pilot whale record from the Faroe Islands offers an exceptional temporal perspective over three centuries. Recent advances in simulating the dynamics of the subpolar gyre suggests a potential for predicting the distribution of the main faunistic zones in the north-eastern Atlantic a few years into the future, which might facilitate a more rational management of the commercially important fisheries in this region.

  9. Observed linkages between the northern annular mode/North Atlantic Oscillation, cloud incidence, and cloud radiative forcing

    Science.gov (United States)

    Li, Ying; Thompson, David W. J.; Huang, Yi; Zhang, Minghong

    2014-03-01

    The signature of the northern annular mode/North Atlantic Oscillation (NAM/NAO) in the vertical and horizontal distribution of tropospheric cloudiness is investigated in CloudSat and CALIPSO data from June 2006 to April 2011. During the Northern Hemisphere winter, the positive polarity of the NAM/NAO is marked by increases in zonally averaged cloud incidence north of ~60°N, decreases between ~25 and 50°N, and increases in the subtropics. The tripolar-like anomalies in cloud incidence associated with the NAM/NAO are largest over the North Atlantic Ocean basin/Middle East and are physically consistent with the NAM/NAO-related anomalies in vertical motion. Importantly, the NAM/NAO-related anomalies in tropospheric cloud incidence lead to significant top of atmosphere cloud radiative forcing anomalies that are comparable in amplitude to those associated with the NAM/NAO-related temperature anomalies. The results provide observational evidence that the most prominent pattern of Northern Hemisphere climate variability is significantly linked to variations in cloud radiative forcing. Implications for two-way feedback between extratropical dynamics and cloud radiative forcing are discussed.

  10. Variations of Sea Surface Temperature, Wind Stress, and Rainfall over the Tropical Atlantic and South America.

    Science.gov (United States)

    Nobre, Paulo; Srukla, J.

    1996-10-01

    Empirical orthogonal functions (E0Fs) and composite analyses are used to investigate the development of sea surface temperature (SST) anomaly patterns over the tropical Atlantic. The evolution of large-scale rainfall anomaly patterns over the equatorial Atlantic and South America are also investigated. 71e EOF analyses revealed that a pattern of anomalous SST and wind stress asymmetric relative to the equator is the dominant mode of interannual and longer variability over the tropical Atlantic. The most important findings of this study are as follows.Atmospheric circulation anomalies precede the development of basinwide anomalous SST patterns over the tropical Atlantic. Anomalous SST originate off the African coast simultaneously with atmospheric circulation anomalies and expand westward afterward. The time lag between wind stress relaxation (strengthening) and maximum SST warming (cooling) is about two months.Anomalous atmospheric circulation patterns over northern tropical Atlantic are phase locked to the seasonal cycle. Composite fields of SLP and wind stress over northern tropical Atlantic can be distinguished from random only within a few months preceding the March-May (MAM) season. Observational evidence is presented to show that the El Niño-Southern Oscillation phenomenon in the Pacific influences atmospheric circulation and SST anomalies over northern tropical Atlantic through atmospheric teleconnection patterns into higher latitudes of the Northern Hemisphere.The well-known droughts over northeastern Brazil (Nordeste) are a local manifestation of a much larger-scale rainfall anomaly pattern encompassing the whole equatorial Atlantic and Amazon region. Negative rainfall anomalies to the south of the equator during MAM, which is the rainy season for the Nordeste region, are related to an early withdrawal of the intertropical convergence zone toward the warm SST anomalies over the northern tropical Atlantic. Also, it is shown that precipitation anomalies

  11. Role of the circulation on the anthropogenic CO2 inventory in the North-East Atlantic: A climatological analysis

    Science.gov (United States)

    Carracedo, L. I.; Pérez, F. F.; Gilcoto, M.; Velo, A.; Padín, A.; Rosón, G.

    2018-02-01

    Climatology-based storage rate of anthropogenic CO2 (Cant, referred to year 2000) in the North-East Atlantic (53 ± 9 kmol s-1, 0.020 ± 0.003 Pg-C yr-1) is described on annual mean terms. Cant advection (32 ± 14 kmol s-1) occurs mostly in the upper 1800 m and contributes to 60% of the Cant storage rate. The Azores and Portugal Currents act as 'Cant streams' importing 389 ± 90 kmol s-1, most of which recirculates southwards with the Canary Current (-214 ± 34 kmol s-1). The Azores Counter Current (-79 ± 36 kmol s-1) and the northward-flowing Mediterranean Water advective branch (-31 ± 12 kmol s-1) comprise secondary Cant export routes. By means of Cant transport decomposition, we find horizontal circulation to represent 11% of the Cant storage rate, while overturning circulation is the main driver (48% of the Cant storage rate). Within the domain of this study, overturning circulation is a key mechanism by which Cant in the upper layer (0-500 dbar) is drawdown (74 ± 14 kmol s-1) to intermediate levels (500-2000 dbar), and entrained (37 ± 7 kmol s-1) into the Mediterranean Outflow Water to form Mediterranean Water. This newly formed water mass partly exports Cant to the North Atlantic at a rate of -39 ± 9 kmol s-1 and partly contributes to the Cant storage in the North-East Atlantic (with up to 0.015 ± 0.006 Pg-C yr-1). Closing the Cant budget, 40% of the Cant storage in the North-East Atlantic is attributable to anthropogenic CO2 uptake from the atmosphere (21 ± 10 kmol s-1).

  12. Nutrients and other data from bottle, MBT, XBT, and CTD casts in the North Atlantic and North Pacific Ocean from 08 May 1956 to 14 December 1999 (NODC Accession 0000717)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Nutrients and other data were collected using bottle, MBT, XBT, and CTD casts in the North Atlantic and North Pacific Ocean from 08 May 1956 to 14 December 1999....

  13. Nutrients and other data from bottle, MBT, XBT, and CTD casts in the North Atlantic and North Pacific Ocean from 03 January 1972 to 16 June 1996 (NODC Accession 0000751)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Nutrients and other data were collected using bottle, MBT, XBT, and CTD casts in the North Atlantic and North Pacific Ocean from 03 January 1972 to 12 June 1996....

  14. Discovery of the oldest record of Nitellopsis obtusa (Charophyceae, Charophyta) in North America.

    Science.gov (United States)

    Karol, Kenneth G; Sleith, Robin S

    2017-10-01

    Studies of the colonization and spread of invasive species improves our understanding of key concepts in population biology as well as informs control and prevention efforts. The characean green alga Nitellopsis obtusa (starry stonewort) is rare in its native Eurasian range but listed by the United States Geological Survey (USGS) as an aggressive invasive in North America. First documented in North America in 1978 from New York, United States, it has since been reported from numerous inland lakes from Minnesota to Vermont, and from Lake Ontario and inland lakes in southern Ontario, Canada. While the ecological impacts of N. obtusa are not clearly understood in its invasive range, initial results show negative environmental effects. We have discovered a liquid-preserved herbarium specimen that predates the 1978 records by at least 4 years, and is the first confirmed record of N. obtusa in Québec. © 2017 Phycological Society of America.

  15. Variability in north tropical atlantic over the last 20 000 years and holocene gulf stream activity

    International Nuclear Information System (INIS)

    Cleroux, C.

    2007-10-01

    Modern oceanographical studies shown that most of the ocean heat content in the North Atlantic Western Boundary Current region is stored in the upper 400 meters. To study past heat content and Gulf Stream activity, we performed coupled analyses of oxygen isotopic and trace elemental composition on several foraminifera species to reconstruct upper water column temperature and salinity. Calcification depths of Globorotalia inflata, Globorotalia truncatulinoides and Pulleniatina obliquiloculata have been constrain by correlating modern hydrographic data to oxygen isotopic measurement of North Atlantic core-top samples. We found that the three deep-dwelling foraminifera species have a preferred habitat at the base of the seasonal thermocline (Cleroux et al, 2007). The same set of North Atlantic core-tops has been used to define relationships between trace elemental compositions and temperature. We established calibrations between Mg/Ca ratio or Sr/Ca ratio and temperature for the three deep-dwelling foraminifera (Cleroux et al, submitted). We apply this strategy on the core MD99-2203 located off Cape Hatteras where the Gulf Stream separate from the United States coast. High-resolution surface reconstructions over the Holocene show low amplitude periodic temperature and salinity changes that could be related to NAO type mechanisms. Large hydrological changes in sub-surface reflect variations of Labrador current and Mode Water influences. Using recent studies on Mode Water formation and Gulf Stream heat advection, we interpret our results in term of ocean heat content and Gulf Stream activity. (author)

  16. Anthropogenic climate change drives shift and shuffle in North Atlantic phytoplankton communities.

    Science.gov (United States)

    Barton, Andrew D; Irwin, Andrew J; Finkel, Zoe V; Stock, Charles A

    2016-03-15

    Anthropogenic climate change has shifted the biogeography and phenology of many terrestrial and marine species. Marine phytoplankton communities appear sensitive to climate change, yet understanding of how individual species may respond to anthropogenic climate change remains limited. Here, using historical environmental and phytoplankton observations, we characterize the realized ecological niches for 87 North Atlantic diatom and dinoflagellate taxa and project changes in species biogeography between mean historical (1951-2000) and future (2051-2100) ocean conditions. We find that the central positions of the core range of 74% of taxa shift poleward at a median rate of 12.9 km per decade (km⋅dec(-1)), and 90% of taxa shift eastward at a median rate of 42.7 km⋅dec(-1) The poleward shift is faster than previously reported for marine taxa, and the predominance of longitudinal shifts is driven by dynamic changes in multiple environmental drivers, rather than a strictly poleward, temperature-driven redistribution of ocean habitats. A century of climate change significantly shuffles community composition by a basin-wide median value of 16%, compared with seasonal variations of 46%. The North Atlantic phytoplankton community appears poised for marked shift and shuffle, which may have broad effects on food webs and biogeochemical cycles.

  17. Reconstructing Late Holocene North Atlantic atmospheric circulation changes using functional paleoclimate networks

    Science.gov (United States)

    Franke, Jasper G.; Werner, Johannes P.; Donner, Reik V.

    2017-11-01

    Obtaining reliable reconstructions of long-term atmospheric circulation changes in the North Atlantic region presents a persistent challenge to contemporary paleoclimate research, which has been addressed by a multitude of recent studies. In order to contribute a novel methodological aspect to this active field, we apply here evolving functional network analysis, a recently developed tool for studying temporal changes of the spatial co-variability structure of the Earth's climate system, to a set of Late Holocene paleoclimate proxy records covering the last two millennia. The emerging patterns obtained by our analysis are related to long-term changes in the dominant mode of atmospheric circulation in the region, the North Atlantic Oscillation (NAO). By comparing the time-dependent inter-regional linkage structures of the obtained functional paleoclimate network representations to a recent multi-centennial NAO reconstruction, we identify co-variability between southern Greenland, Svalbard, and Fennoscandia as being indicative of a positive NAO phase, while connections from Greenland and Fennoscandia to central Europe are more pronounced during negative NAO phases. By drawing upon this correspondence, we use some key parameters of the evolving network structure to obtain a qualitative reconstruction of the NAO long-term variability over the entire Common Era (last 2000 years) using a linear regression model trained upon the existing shorter reconstruction.

  18. Fall spawning of Atlantic sturgeon in the Roanoke River, North Carolina

    Science.gov (United States)

    Smith, Joseph A.; Hightower, Joseph E.; Flowers, H. Jared

    2015-01-01

    In 2012, the National Oceanic and Atmospheric Administration (NOAA) declared Atlantic Sturgeon Acipenser oxyrinchus oxyrinchus to be threatened or endangered throughout its range in U.S. waters. Restoration of the subspecies will require much new information, particularly on the location and timing of spawning. We used a combination of acoustic telemetry and sampling with anchored artificial substrates (spawning pads) to detect fall (September–November) spawning in the Roanoke River in North Carolina. This population is included in the Carolina Distinct Population Segment, which was classified by NOAA as endangered. Sampling was done immediately below the first shoals encountered by anadromous fishes, near Weldon. Our collection of 38 eggs during the 21 d that spawning pads were deployed appears to be the first such collection (spring or fall) for wild-spawned Atlantic Sturgeon eggs. Based on egg development stages, estimated spawning dates were September 17–18 and 18–19 at water temperatures from 25.3°C to 24.3°C and river discharge from 55 to 297 m3/s. These observations about fall spawning and habitat use should aid in protecting critical habitats and planning research on Atlantic Sturgeon spawning in other rivers.

  19. Implications for anomalous mantle pressure and dynamic topography from lithospheric stress patterns in the North Atlantic Realm

    Science.gov (United States)

    Schiffer, Christian; Nielsen, Søren Bom

    2016-08-01

    With convergent plate boundaries at some distance, the sources of the lithospheric stress field of the North Atlantic Realm are mainly mantle tractions at the base of the lithosphere, lithospheric density structure and topography. Given this, we estimate horizontal deviatoric stresses using a well-established thin sheet model in a global finite element representation. We adjust the lithospheric thickness and the sub-lithospheric pressure iteratively, comparing modelled in plane stress with the observations of the World Stress Map. We find that an anomalous mantle pressure associated with the Iceland and Azores melt anomalies, as well as topography are able to explain the general pattern of the principle horizontal stress directions. The Iceland melt anomaly overprints the classic ridge push perpendicular to the Mid Atlantic ridge and affects the conjugate passive margins in East Greenland more than in western Scandinavia. The dynamic support of topography shows a distinct maximum of c. 1000 m in Iceland and amounts <150 m along the coast of south-western Norway and 250-350 m along the coast of East Greenland. Considering that large areas of the North Atlantic Realm have been estimated to be sub-aerial during the time of break-up, two components of dynamic topography seem to have affected the area: a short-lived, which affected a wider area along the rift system and quickly dissipated after break-up, and a more durable in the close vicinity of Iceland. This is consistent with the appearance of a buoyancy anomaly at the base of the North Atlantic lithosphere at or slightly before continental breakup, relatively fast dissipation of the fringes of this, and continued melt generation below Iceland.

  20. Data-driven diagnostics of terrestrial carbon dynamics over North America

    Science.gov (United States)

    Jingfeng Xiao; Scott V. Ollinger; Steve Frolking; George C. Hurtt; David Y. Hollinger; Kenneth J. Davis; Yude Pan; Xiaoyang Zhang; Feng Deng; Jiquan Chen; Dennis D. Baldocchi; Bevery E. Law; M. Altaf Arain; Ankur R. Desai; Andrew D. Richardson; Ge Sun; Brian Amiro; Hank Margolis; Lianhong Gu; Russell L. Scott; Peter D. Blanken; Andrew E. Suyker

    2014-01-01

    The exchange of carbon dioxide is a key measure of ecosystem metabolism and a critical intersection between the terrestrial biosphere and the Earth's climate. Despite the general agreement that the terrestrial ecosystems in North America provide a sizeable carbon sink, the size and distribution of the sink remain uncertain. We use a data-driven approach to upscale...

  1. Bark beetle outbreaks in western North America: Causes and consequences

    Science.gov (United States)

    Bentz, Barbara; Logan, Jesse; MacMahon, James A.; Allen, Craig D.; Ayres, Matt; Berg, Edward E; Carroll, Allan; Hansen, Matt; Hicke, Jeff H.; Joyce, Linda A.; Macfarlane, Wallace; Munson, Steve; Negron, Jose; Paine, Tim; Powell, Jim; Raffa, Kenneth; Regniere, Jacques; Reid, Mary; Romme, Bill; Seybold, Steven J.; Six, Diana; Vandygriff, Jim; Veblen, Tom; White, Mike; Witcosky, Jeff; Wood, David J. A.

    2005-01-01

    Since 1990, native bark beetles have killed billions of trees across millions of acres of forest from Alaska to northern Mexico. Although bark beetle infestations are a regular force of natural change in forested ecosystems, several of the current outbreaks, which are occurring simultaneously across western North America, are the largest and most severe in recorded history.

  2. An Overview of CLT Research and Implementation in North America

    Science.gov (United States)

    Shiling Pei; Douglas Rammer; Marjan Popovski; Tom Williamson; Philip Line; John W. van de Lindt

    2016-01-01

    Although not yet seen as common practice, building with cross laminated timber (CLT) is gaining momentum in North America. Behind the scenes of the widely publicized project initiatives such as the Wood Innovation Design Centre Building in Canada and the recent U.S. Tall Wood Building Competition, substantial research, engineering, and development has been completed or...

  3. Parasites of freshwater fishes in North America: why so neglected?

    Science.gov (United States)

    Scholz, Tomáš; Choudhury, Anindo

    2014-02-01

    Fish parasitology has a long tradition in North America and numerous parasitologists have contributed considerably to the current knowledge of the diversity and biology of protistan and metazoan parasites of freshwater fishes. The Journal of Parasitology has been essential in disseminating this knowledge and remains a significant contributor to our understanding of fish parasites in North America as well as more broadly at the international level. However, with a few exceptions, the importance of fish parasites has decreased during the last decades, which is reflected in the considerable decline of funding and corresponding decrease of attention paid to these parasites in Canada and the United States of America. After the 'golden age' in the second half of the 20th Century, fish parasitology in Canada and the United States went in a new direction, driven by technology and a shift in priorities. In contrast, fish parasitology in Mexico has undergone rapid development since the early 1990s, partly due to extensive international collaboration and governmental funding. A critical review of the current data on the parasites of freshwater fishes in North America has revealed considerable gaps in the knowledge of their species composition, host specificity, life cycles, evolution, phylogeography, and relationships with their fish hosts. As to the key question, "Why so neglected?" this is probably because: (1) fish parasites are not in the forefront due to their lesser economic importance; (2) there is little funding for this kind of research, especially if a practical application is not immediately apparent; and (3) of shifting interests and a shortage of key personalities to train a new generation (they switched to marine habitats or other fields). Some of the opportunities for future research are outlined, such as climate change and cryptic species diversity. A significant problem challenging future research seems to be the loss of trained and experienced fish

  4. Dissolution of calcium carbonate: observations and model results in the subpolar North Atlantic

    Directory of Open Access Journals (Sweden)

    K. Friis

    2007-01-01

    Full Text Available We investigate the significance of in situ dissolution of calcium carbonate above its saturation horizons using observations from the open subpolar North Atlantic [sNA] and to a lesser extent a 3-D biogeochemical model. The sNA is particularly well suited for observation-based detections of in situ, i.e. shallow-depth CaCO3 dissolution [SDCCD] as it is a region of high CaCO3 production, deep CaCO3 saturation horizons, and precisely-defined pre-formed alkalinity. Based on the analysis of a comprehensive alkalinity data set we find that SDCCD does not appear to be a significant process in the open sNA. The results from the model support the observational findings by indicating that there is not a significant need of SDCCD to explain observed patterns of alkalinity in the North Atlantic. Instead our investigation points to the importance of mixing processes for the redistribution of alkalinity from dissolution of CaCO3 from below its saturation horizons. However, mixing has recently been neglected for a number of studies that called for SDCCD in the sNA and on global scale.

  5. The emerald ash borer: a new exotic pest in North America

    Science.gov (United States)

    Robert A. Haack; Eduard Jendak; Liu Houping; Keneth R. Marchant; Toby R. Petrice; Therese M. Poland; Hui Ye

    2002-01-01

    Yet another new exotic forest pest has been discovered in North America, and this time the infestation is centered in Michigan and Ontario. In May and June 2002, adults of an unidentified buprestid beetle were collected from ash (Fraxinus) trees in the Detroit area of southeastern Michigan.

  6. Whales, Dolphins, and Porpoises of the Western North Atlantic: A Guide to Their Identification.

    Science.gov (United States)

    Leatherwood, Stephen; And Others

    This field guide is designed to permit observers to identify the cetaceans (whales, dolphins, and porpoises) they see in western North Atlantic, including the Caribbean Sea, the Gulf of Mexico, and the coastal waters of the United States and Canada. The animals described are not grouped by scientific relationships but by similarities in appearance…

  7. Connectivity between surface and deep waters determines prokaryotic diversity in the North Atlantic Deep Water.

    Science.gov (United States)

    Frank, Alexander H; Garcia, Juan A L; Herndl, Gerhard J; Reinthaler, Thomas

    2016-06-01

    To decipher the influence of depth stratification and surface provincialism on the dark ocean prokaryotic community composition, we sampled the major deep-water masses in the eastern North Atlantic covering three biogeographic provinces. Their diversity was evaluated using ordination and canonical analysis of 454 pyrotag sequences. Variance partitioning suggested that 16% of the variation in the bacterial community composition was based on depth stratification while 9% of the variation was due to geographic location. General linear mixed effect models showed that the community of the subsurface waters was connected to the dark ocean prokaryotic communities in different biogeographic provinces. Cluster analysis indicated that some prokaryotic taxa are specific to distinct regions in bathypelagic water masses. Taken together, our data suggest that the dark ocean prokaryotic community composition of the eastern North Atlantic is primed by the formation and the horizontal transport of water masses. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  8. Scales of North Atlantic wind stress curl determined from the comprehensive ocean-atmosphere data set

    Science.gov (United States)

    Ehret, Laura L.; O'Brien, James J.

    1989-01-01

    Nineteen years of wind data over the North Atlantic are used to calculate a field of wind stress curl. An empirical orthogonal function (EOF) analysis is performed on this field, resulting in spatial patterns of wind stress curl and associated time series. A Monte Carlo technique is used to establish the statistical significance of each spatial pattern, and the associated time series are spectrally analyzed. The first four statistically significant EOF modes represent more than 50 percent of the curl variance, and the spatial patterns of curl associated with these modes exhibit the major elements of North Atlantic climatology. Most of the time series spectral variance is contained in annual and semiannual frequencies. The features observed include the individual annual variation of the subtropical high and the subpolar low, the annual oscillation of intensity between pressure centers, the influence of localized strong SST gradients and associated cyclogenesis regions, and the constant nature of the trades.

  9. Patterns of admixture and population structure in native populations of Northwest North America.

    Directory of Open Access Journals (Sweden)

    Paul Verdu

    2014-08-01

    Full Text Available The initial contact of European populations with indigenous populations of the Americas produced diverse admixture processes across North, Central, and South America. Recent studies have examined the genetic structure of indigenous populations of Latin America and the Caribbean and their admixed descendants, reporting on the genomic impact of the history of admixture with colonizing populations of European and African ancestry. However, relatively little genomic research has been conducted on admixture in indigenous North American populations. In this study, we analyze genomic data at 475,109 single-nucleotide polymorphisms sampled in indigenous peoples of the Pacific Northwest in British Columbia and Southeast Alaska, populations with a well-documented history of contact with European and Asian traders, fishermen, and contract laborers. We find that the indigenous populations of the Pacific Northwest have higher gene diversity than Latin American indigenous populations. Among the Pacific Northwest populations, interior groups provide more evidence for East Asian admixture, whereas coastal groups have higher levels of European admixture. In contrast with many Latin American indigenous populations, the variance of admixture is high in each of the Pacific Northwest indigenous populations, as expected for recent and ongoing admixture processes. The results reveal some similarities but notable differences between admixture patterns in the Pacific Northwest and those in Latin America, contributing to a more detailed understanding of the genomic consequences of European colonization events throughout the Americas.

  10. The Energy Cascade Associated with the North Atlantic Oscillation

    Science.gov (United States)

    Castanheira, J. M.; Marques, C. A. F.

    2017-12-01

    The North Atlantic Oscillation or Arctic Oscillation (NAO/AO), in a more hemispheric expression, is the dominant mode of variability of the extratropical atmospheric circulation. In the literature which analyses the association of low frequency variability of the NAO/AO with other climate variables, it is very common to find the idea of circulation and climate impacts of the NAO/AO. It is usually suggested that the NAO influences the position of North Atlantic storm tracks and the related transport of heat and moisture. However, in spite of the long time since the NAO variability mode was uncovered (Walker and Bliss, 1932), its underlying dynamical mechanisms are not well understood yet. In fact, it is not yet consensual that the NAO influences the position of the storm tracks, being possible that the relationship is in the opposite way with the storm track activity influencing de NAO. In this communication we will present an analysis of anomalies of the energy cascade associated with the NAO. A detailed version of the Lorenz energy cycle, which decomposes the energy flows into baroclinic and barotropic terms and into zonal mean and eddy components, was applied to the 6-hourly ERA-I reanalysis for the period of 1979 to 2016. The obtained results show that the positive NAO phase is preceded by an significant increase of synoptic baroclinic eddy activity. The eddy available potential energy is converted into kinetic energy and transferred to barotropic synoptic eddies. Then, the kinetic energy is transferred upscale into the barotropic planetary waves, which reproduce the NAO pattern. Therefore, we conclude that the synoptic baroclinic eddy activity forces the NAO variability. No clear signal was found for a modulating role of the NAO in the baroclinic eddy activity.

  11. Environmental imperatives reconsidered: demographic crises in western North America during the medieval climatic anomaly.

    Science.gov (United States)

    Jones, T L; Brown, G M; Raab, L M; McVickar, J L; Spaulding, W G; Kennett, D J; York, A; Wlaker, P L

    1999-04-01

    Review of late Holocene paleoenvironmental and cultural sequences from four regions of western North America show striking correlations between drought and changes in subsistence, population, exchange, health, and interpersonal violence during the Medieval Climatic Anomaly (A.D. 800-1350). While ultimate causality is difficult to identify in the archaeological record, synchrony of the environmental and cultural changes and the negative character of many human responses--increased interpersonal violence, deterioration of long-distance exchange relationships, and regional abandonments--suggest widespread demographic crises caused by decreased environmental productivity. The medieval droughts occurred at a unique juncture in the demographic history of western North America when unusually large populations of both hunter-gathers and agriculturalists had evolved highly intensified economies that put them in unprecedented ecological jeopardy. Long-term patterns in the archaeological record are inconsistent with the predicted outcomes of simple adaptation or continuous economic intensification, suggesting that in this instance environmental dynamics played a major role in cultural transformations across a wide expanse of western North America among groups with diverse subsistence strategies. These events suggest that environment should not be overlooked as a potential cause of prehistoric culture change.

  12. An Anatomy of the 1960s Atlantic Cooling.

    Science.gov (United States)

    Hodson, Dan; Robson, Jon; Sutton, Rowan

    2014-05-01

    North Atlantic Sea Surface Temperatures (SSTs) exhibited pronounced multidecadal variability during the 20th Century. In particular, the North Atlantic SSTs exhibited a rapid warming between 1920 and 1940 followed by a rapid cooling between 1960 and 1980. SSTs outside the North Atlantic display a much smaller level of decadal variability over the 20th Century. This pattern of North Atlantic warming and cooling has been linked to subsequent changes in rainfall over the Sahel and Nordeste Brazil, Summertime North American Climate and Atlantic Hurricane Genesis. Several hypotheses for the rapid 1960s Atlantic cooling have been proposed, including a reduction in northward ocean heat transport due to a reduced Atlantic Meridional Overturning Circulation (AMOC) and the significant rise in anthropogenic sulphur dioxide emissions during the latter half of the 20th century. Here we examine the observed 1960s Atlantic cooling in more detail. We describe the evolution of the rapid cooling by constructing a detailed multivariate anatomy of the cooling period in order to illuminate the possible explanations and mechanisms involved. We show that the observed 1960s cooling began around 1964-68 in the Greenland-Iceland-Norway (GIN) seas, later spreading to the Atlantic Sub Polar Gyre and much of the subtropical Atlantic. This initial cooling of the Sub Polar Gyre is associated with a marked reduction in salinity (the Great Salinity Anomaly). The cooling peaked between 1972-76, extending into the Tropical North Atlantic. This period also saw the development of a significant Winter North-South Dipole Mean Sea Level Pressure dipole pattern reminiscent of a positive NAO (High over the Azores, Low over Iceland). The cooling then retreated back to higher latitudes during 1976:80. Our analysis demonstrates that the cooling of the North Atlantic during the 1960s cannot be understood as a simple thermodynamic response to aerosol induced reductions in shortwave radiation. Dynamical changes

  13. The Asian-Bering-North American teleconnection: seasonality, maintenance, and climate impact on North America

    Science.gov (United States)

    Yu, Bin; Lin, H.; Wu, Z. W.; Merryfield, W. J.

    2018-03-01

    The Asian-Bering-North American (ABNA) teleconnection index is constructed from the normalized 500-hPa geopotential field by excluding the Pacific-North American pattern contribution. The ABNA pattern features a zonally elongated wavetrain originating from North Asia and flowing downstream across Bering Sea and Strait towards North America. The large-scale teleconnection is a year-round phenomenon that displays strong seasonality with the peak variability in winter. North American surface temperature and temperature extremes, including warm days and nights as well as cold days and nights, are significantly controlled by this teleconnection. The ABNA pattern has an equivalent barotropic structure in the troposphere and is supported by synoptic-scale eddy forcing in the upper troposphere. Its associated sea surface temperature anomalies exhibit a horseshoe-shaped structure in the North Pacific, most prominent in winter, which is driven by atmospheric circulation anomalies. The snow cover anomalies over the West Siberian plain and Central Siberian Plateau in autumn and spring and over southern Siberia in winter may act as a forcing influence on the ABNA pattern. The snow forcing influence in winter and spring can be traced back to the preceding season, which provides a predictability source for this teleconnection and for North American temperature variability. The ABNA associated energy budget is dominated by surface longwave radiation anomalies year-round, with the temperature anomalies supported by anomalous downward longwave radiation and damped by upward longwave radiation at the surface.

  14. Decadal Declines of Mercury in Adult Bluefish (1972-2011) from the Mid-Atlantic Coast of the U.S.A.

    Science.gov (United States)

    Cross, Ford A; Evans, David W; Barber, Richard T

    2015-08-04

    Concentrations of total mercury were measured in muscle of adult bluefish (Pomatomus saltatrix) collected in 2011 off North Carolina and compared with similar measurements made in 1972. Concentrations of mercury decreased by 43% in the fish between the two time periods, with an average rate of decline of about 10% per decade. This reduction is similar to estimated reductions of mercury observed in atmospheric deposition, riverine input, seawater, freshwater lakes, and freshwater fish across northern North America. Eight other studies between 1973 and 2007 confirm the decrease in mercury levels in bluefish captured in the Mid-Atlantic Bight. These findings imply that (1) reductions in the release of mercury across northern North America were reflected rather quickly (decades) in the decline of mercury in adult bluefish; (2) marine predatory fish may have been contaminated by anthropogenic sources of mercury for over 100 years; and (3) if bluefish are surrogates for other predators in the Mid-Atlantic Bight, then a reduction in the intake of mercury by the fish-consuming public has occurred. Finally, with global emissions of mercury continuing to increase, especially from Asia, it is important that long-term monitoring programs be conducted for mercury in marine fish of economic importance.

  15. Water mass distributions and transports for the 2014 GEOVIDE cruise in the North Atlantic

    Science.gov (United States)

    García-Ibáñez, Maribel I.; Pérez, Fiz F.; Lherminier, Pascale; Zunino, Patricia; Mercier, Herlé; Tréguer, Paul

    2018-04-01

    We present the distribution of water masses along the GEOTRACES-GA01 section during the GEOVIDE cruise, which crossed the subpolar North Atlantic Ocean and the Labrador Sea in the summer of 2014. The water mass structure resulting from an extended optimum multiparameter (eOMP) analysis provides the framework for interpreting the observed distributions of trace elements and their isotopes. Central Waters and Subpolar Mode Waters (SPMW) dominated the upper part of the GEOTRACES-GA01 section. At intermediate depths, the dominant water mass was Labrador Sea Water, while the deep parts of the section were filled by Iceland-Scotland Overflow Water (ISOW) and North-East Atlantic Deep Water. We also evaluate the water mass volume transports across the 2014 OVIDE line (Portugal to Greenland section) by combining the water mass fractions resulting from the eOMP analysis with the absolute geostrophic velocity field estimated through a box inverse model. This allowed us to assess the relative contribution of each water mass to the transport across the section. Finally, we discuss the changes in the distribution and transport of water masses between the 2014 OVIDE line and the 2002-2010 mean state. At the upper and intermediate water levels, colder end-members of the water masses replaced the warmer ones in 2014 with respect to 2002-2010, in agreement with the long-term cooling of the North Atlantic Subpolar Gyre that started in the mid-2000s. Below 2000 dbar, ISOW increased its contribution in 2014 with respect to 2002-2010, with the increase being consistent with other estimates of ISOW transports along 58-59° N. We also observed an increase in SPMW in the East Greenland Irminger Current in 2014 with respect to 2002-2010, which supports the recent deep convection events in the Irminger Sea. From the assessment of the relative water mass contribution to the Atlantic Meridional Overturning Circulation (AMOC) across the OVIDE line, we conclude that the larger AMOC intensity in

  16. North Atlantic ocean circulation and abrupt climate change during the last glaciation.

    Science.gov (United States)

    Henry, L G; McManus, J F; Curry, W B; Roberts, N L; Piotrowski, A M; Keigwin, L D

    2016-07-29

    The most recent ice age was characterized by rapid and hemispherically asynchronous climate oscillations, whose origin remains unresolved. Variations in oceanic meridional heat transport may contribute to these repeated climate changes, which were most pronounced during marine isotope stage 3, the glacial interval 25 thousand to 60 thousand years ago. We examined climate and ocean circulation proxies throughout this interval at high resolution in a deep North Atlantic sediment core, combining the kinematic tracer protactinium/thorium (Pa/Th) with the deep water-mass tracer, epibenthic δ(13)C. These indicators suggest reduced Atlantic overturning circulation during every cool northern stadial, with the greatest reductions during episodic Hudson Strait iceberg discharges, while sharp northern warming followed reinvigorated overturning. These results provide direct evidence for the ocean's persistent, central role in abrupt glacial climate change. Copyright © 2016, American Association for the Advancement of Science.

  17. Comparative ecology of widely distributed pelagic fish species in the North Atlantic: Implications for modelling climate and fisheries impacts

    Science.gov (United States)

    Trenkel, V. M.; Huse, G.; MacKenzie, B. R.; Alvarez, P.; Arrizabalaga, H.; Castonguay, M.; Goñi, N.; Grégoire, F.; Hátún, H.; Jansen, T.; Jacobsen, J. A.; Lehodey, P.; Lutcavage, M.; Mariani, P.; Melvin, G. D.; Neilson, J. D.; Nøttestad, L.; Óskarsson, G. J.; Payne, M. R.; Richardson, D. E.; Senina, I.; Speirs, D. C.

    2014-12-01

    This paper reviews the current knowledge on the ecology of widely distributed pelagic fish stocks in the North Atlantic basin with emphasis on their role in the food web and the factors determining their relationship with the environment. We consider herring (Clupea harengus), mackerel (Scomber scombrus), capelin (Mallotus villosus), blue whiting (Micromesistius poutassou), and horse mackerel (Trachurus trachurus), which have distributions extending beyond the continental shelf and predominantly occur on both sides of the North Atlantic. We also include albacore (Thunnus alalunga), bluefin tuna (Thunnus thynnus), swordfish (Xiphias gladius), and blue marlin (Makaira nigricans), which, by contrast, show large-scale migrations at the basin scale. We focus on the links between life history processes and the environment, horizontal and vertical distribution, spatial structure and trophic role. Many of these species carry out extensive migrations from spawning grounds to nursery and feeding areas. Large oceanographic features such as the North Atlantic subpolar gyre play an important role in determining spatial distributions and driving variations in stock size. Given the large biomasses of especially the smaller species considered here, these stocks can exert significant top-down pressures on the food web and are important in supporting higher trophic levels. The review reveals commonalities and differences between the ecology of widely distributed pelagic fish in the NE and NW Atlantic basins, identifies knowledge gaps and modelling needs that the EURO-BASIN project attempts to address.

  18. A Mixed Integer Linear Programming Model for the North Atlantic Aircraft Trajectory Planning

    OpenAIRE

    Sbihi , Mohammed; Rodionova , Olga; Delahaye , Daniel; Mongeau , Marcel

    2015-01-01

    International audience; This paper discusses the trajectory planning problem for ights in the North Atlantic oceanic airspace (NAT). We develop a mathematical optimization framework in view of better utilizing available capacity by re-routing aircraft. The model is constructed by discretizing the problem parameters. A Mixed integer linear program (MILP) is proposed. Based on the MILP a heuristic to solve real-size instances is also introduced

  19. Global warming and stress complexes in forests of western North America

    Science.gov (United States)

    Donald McKenzie; David L. Peterson; Jeremy J. Littell

    2009-01-01

    A warmer climate in western North America will likely affect forests directly through soil moisture stress and indirectly through increased extent and severity of disturbances. We propose that stress complexes, combinations of biotic and abiotic stresses, compromise the vigor and ultimate sustainability of forest ecosystems. Across...

  20. Coastal Sea Level along the North Eastern Atlantic Shelf from Delay Doppler Altimetry

    Science.gov (United States)

    Fenoglio-Marc, L.; Benveniste, J.; Andersen, O. B.; Gravelle, M.; Dinardo, S.; Uebbing, B.; Scharroo, R.; Kusche, J.; Kern, M.; Buchhaupt, C.

    2017-12-01

    Satellite altimetry data of the CryoSat-2 and Sentinel-3 missions processed with Delay Doppler methodology (DDA) provide improved coastal sea level measurements up to 2-4 km from coast, thanks to an along-track resolution of about 300m and a higher signal to noise ratio. We investigate the 10 Kilometre stripe along the North-Eastern Atlantic shelf from Lisbon to Bergen to detect the possible impacts in sea level change studies of this enhanced dataset. We consider SAR CryoSat-2 and Sentinel-3 altimetry products from the ESA GPOD processor and in-house reduced SAR altimetry (RDSAR) products. Improved processing includes in RDSAR the application of enhanced retrackers for the RDSAR waveform. Improved processing in SAR includes modification both in the generation of SAR waveforms, (as Hamming weighting window on the burst data prior to the azimuth FFT, zero-padding prior to the range FFT, doubling of the extension for the radar range swath) and in the SAMOSA2 retracker. Data cover the full lifetime of CryoSat-2 (6 years) and Sentinel-3 (1 year). Conventional altimetry are from the sea level CCI database. First we analyse the impact of these SAR altimeter data on the sea level trend and on the estimation of vertical motion from the altimeter minus tide gauge differences. VLM along the North-Eastern Atlantic shelf is generally small compared to the North-Western Atlantic Coast VLM, with a smaller signal to noise ratio. Second we investigate impact on the coastal mean sea level surface and the mean dynamic topography. We evaluate a mean surface from the new altimeter data to be combined to state of the art geoid models to derive the mean dynamic topography. We compare the results to existing oceanographic and geodetic mean dynamic topography solutions, both on grid and pointwise at the tide gauge stations. This study is supported by ESA through the Sea Level CCI and the GOCE++DYCOT projects

  1. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from KNORR in the North Atlantic Ocean, North Greenland Sea and others from 1972-07-18 to 1973-04-01 (NCEI Accession 0143398)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0143398 includes discrete sample and profile data collected from KNORR in the North Atlantic Ocean, North Greenland Sea, Norwegian Sea, South Atlantic...

  2. Impact of ice sheet induced North Atlantic oscillation on East Asian summer monsoon during an interglacial 500,000 years ago

    Energy Technology Data Exchange (ETDEWEB)

    Sundaram, S.; Yin, Q.Z.; Berger, A.; Muri, H. [Universite Catholique de Louvain, Earth and Life Institute (ELI), Georges Lemaitre Centre for Earth and Climate Research (TECLIM), Louvain la Neuve (Belgium)

    2012-09-15

    Marine Isotope Stage (MIS) 13, an interglacial about 500,000 years ago, is unique due to an exceptionally strong East Asia summer monsoon (EASM) occurring in a relatively cool climate with low greenhouse gas concentrations (GHG). This paper attempts to find one of the possible mechanisms for this seeming paradox. Simulations with an Earth System model LOVECLIM show that the presence of ice sheets over North America and Eurasia during MIS-13 induces a positive phase of the winter North Atlantic Oscillation (NAO) like feature. The ocean having a longer memory than the atmosphere, the oceanic anomalies associated with NAO persists until summer. The signals of summer NAO are transmitted to East Asia to reinforce the monsoon there through the stationary waves excited at the Asian Jet entrance. The geopotential height shows clearly a mid-latitude wave train with positive anomalies over the eastern Mediterranean/Caspian Sea and the Okhotsk Sea and a negative anomaly over Lake Baikal. This reinforces the effect of the high-latitude wave train induced independently by the Eurasian ice sheet topography as shown in previous study. These features reinforce the Meiyu front and enhance the precipitation over East Asia. The results obtained from LOVECLIM are further confirmed by an atmospheric general circulation model, ARPEGE. (orig.)

  3. Variability of tropical cyclone rapid intensification in the North Atlantic and its relationship with climate variations

    Science.gov (United States)

    Wang, Chunzai; Wang, Xidong; Weisberg, Robert H.; Black, Michael L.

    2017-12-01

    The paper uses observational data from 1950 to 2014 to investigate rapid intensification (RI) variability of tropical cyclones (TCs) in the North Atlantic and its relationships with large-scale climate variations. RI is defined as a TC intensity increase of at least 15.4 m/s (30 knots) in 24 h. The seasonal RI distribution follows the seasonal TC distribution, with the highest number in September. Although an RI event can occur anywhere over the tropical North Atlantic (TNA), there are three regions of maximum RI occurrence: (1) the western TNA of 12°N-18°N and 60°W-45°W, (2) the Gulf of Mexico and the western Caribbean Sea, and (3) the open ocean southeast and east of Florida. RI events also show a minimum value in the eastern Caribbean Sea north of South America—a place called a hurricane graveyard due to atmospheric divergence and subsidence. On longer time scales, RI displays both interannual and multidecadal variability, but RI does not show a long-term trend due to global warming. The top three climate indices showing high correlations with RI are the June-November ENSO and Atlantic warm pool indices, and the January-March North Atlantic oscillation index. It is found that variabilities of vertical wind shear and TC heat potential are important for TC RI in the hurricane main development region, whereas relative humidity at 500 hPa is the main factor responsible for TC RI in the eastern TNA. However, the large-scale oceanic and atmospheric variables analyzed in this study do not show an important role in TC RI in the Gulf of Mexico and the open ocean southeast and east of Florida. This suggests that other factors such as small-scale changes of oceanic and atmospheric variables or TC internal processes may be responsible for TC RI in these two regions. Additionally, the analyses indicate that large-scale atmospheric and oceanic variables are not critical to TC genesis and formation; however, once a tropical depression forms, large-scale climate

  4. Gateways and Water Mass Mixing in the Late Cretaceous North Atlantic

    Science.gov (United States)

    Asgharian Rostami, M.; Martin, E. E.; MacLeod, K. G.; Poulsen, C. J.; Vande Guchte, A.; Haynes, S.

    2017-12-01

    Regions of intermediate/deep water formation and water-mass mixing in the North Atlantic are poorly defined for the Late Cretaceous, a time of gateway evolution and cooler conditions following the Mid Cretaceous greenhouse. Improved proxy data combined with modeling efforts are required to effectively evaluate the relationship between CO2, paleogeography, and circulation during this cooler interval. We analyzed and compiled latest Cretaceous (79 - 66 Ma) ɛNd and δ13C records from seven bathyal (paleodepths 0.2 - 2 km) and eight abyssal (paleodepths > 2 km) sites in the North Atlantic. Data suggest local downwelling of Northern Component Water (NCW; ɛNd -9.5 and δ13C 1.7 ‰) is the primary source of intermediate/deep water masses in the basin. As this water flows southward and ages, δ13C values decrease and ɛNd values increase; however, additional chemical changes at several sites require mixing with contributions from several additional water masses. Lower ɛNd ( -10) and higher δ13C ( 1.9 ‰) values in the deep NW part of the basin indicate proximal contributions from a region draining old continental crust, potentially representing deep convection following opening of the Labrador Sea. In the deep NE Iberian Basin, higher ɛNd ( -7) and lower δ13C ( 0.8 ‰) during the Campanian suggest mixing with a Tethyan source (ɛNd -7 and δ13C 0.1 ‰) whose importance decreased with restriction of that gateway in the Maastrichtian. Data from bathyal sites suggest additional mixing. In the SE Cape Verde region, observed ɛNd variations from -10 in the Campanian to -13 and -12 in the early and late Maastrichtian, respectively, may record variations in output rates of Tethyan and/or NCW sources and Demerara Bottom Water (ɛNd -16), a proposed warm saline intermediate water mass formed in shallow, equatorial seas. Pacific inflow through the Caribbean gateway impacts intermediate sites at Blake Nose (ɛNd values -8), particularly the shallowest site during the late

  5. A hypothesis of a redistribution of North Atlantic swordfish based on changing ocean conditions

    Science.gov (United States)

    Schirripa, Michael J.; Abascal, F.; Andrushchenko, Irene; Diaz, Guillermo; Mejuto, Jaime; Ortiz, Maricio; Santos, M. N.; Walter, John

    2017-06-01

    Conflicting trends in indices of abundance for North Atlantic swordfish starting in the mid-to late 1990s, in the form of fleet specific catch-per-unit-effort (CPUE), suggest the possibility of a spatial shift in abundance to follow areas of preferred temperature. The observed changes in the direction of the CPUEs correspond with changes in trends in the summer Atlantic Multidecadal Oscillation (AMO), a long term mode of variability of North Atlantic sea surface temperature. To test the hypothesis of a relation between the CPUE and the AMO, the CPUEs were made spatially explicit by re-estimating using an ;areas-as-fleets; approach. These new CPUEs were then used to create alternative stock histories. The residuals of the fit were then regressed against the summer AMO. Significant, and opposite, relations were found in the regressions between eastern and western Atlantic areas. When the AMO was in a warm phase, the CPUEs in the western (eastern) areas were higher (lower) than predicted by the assessment model fit. Given the observed temperature tolerance limits of swordfish, it is possible that either their preferred habitat, prey species, or both have shifted spatial distributions resulting in conflicting CPUE indices. Because the available CPUE time series only overlaps with one change in the sign of the AMO ( 1995), it is not clear whether this is a directional or cyclical trend. Given the relatively localized nature of many of the fishing fleets, and the difficulty of separating fleet effects from changes in oceanography we feel that it is critical to create CPUE indices by combining data across similar fleets that fish in similar areas. This approach allowed us to evaluate area-specific catch rates which provided the power to detect basin-wide responses to changing oceanography, a critical step for providing robust management advice in a changing climate.

  6. Sustainable energy developments in Europe and North America

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    Europe and North America account for 70% of world energy consumption; 61% of which is fossil fuels. Energy trends and patterns in this region, if pursued, would have a large impact on region- and world-wide energy and ecosystems. This report addresses the issues of whether projected trends and supply structures would be 'sustainable' i.e. meet the needs of the present without compromising the ability of future generations to meet their own needs; what adaptations are warranted; and what role could and should be played by regional energy and environmental co-operation: including through the United Nations Economic Commission for Europe. The report is divided into three parts. Part 1 studies the interrelationships between environmental and energy policies in Europe and North America until 2010 and beyond. Part II contains research notes on CO{sub 2} concentration and energy scenarios; investment requirements of the energy supply industries in the ERE region for 1980-2000; energy technologies for the first decades of the 21st century. Scope and conditions for enhancing energy efficiency in the ERE region; CO{sub 2} and climate variation and its impact on energy policy in the USSR and European CMEA countries; the role of new and renewable sources of energy; projected energy developments in the ERE region until 2010, and pollution: synopsis of various international studies on the sustainability of energy developments. Part III describes the energy program of the UN-ECE.

  7. Why Don’t They Participate? A Self-Study of Chinese Graduate Students’ Classroom:Involvement in North America

    Directory of Open Access Journals (Sweden)

    Chunlei Lu

    2010-07-01

    Full Text Available China is now the world’s largest source of international students. In terms of learning performance, Chinese graduate students studying in North America exhibit distinct differences from students who are born and raised in North America. Conflicting cultural values compel Chinese students to reconcile East-West cultures, and put an onus on North American instructors to implement culturally-sensitive pedagogy. Employing the theoretic framework of yin-yang theory, this paper examines Chinese graduate students’ classroom performance against the backdrop of East-West cultural negotiation, and specifically seeks to identify which factors inhibit Chinese graduate students’ participation in North American classrooms. Drawing from their own living experiences, the authors employ self-study in the methodological form of narrative inquiry – in conjunction with references from existing literature – to investigate Chinese graduates’ classroom challenges. Results reveal six factors impacting students’ classroom performance: language; knowledge of the education system; knowledge of the social system; personality; influence of traditional culture; and social/economic/political changes. Future research directions are also suggested.Key words: Chinese graduates, East-West, cross-culture, North America, classroom involvement, self-study 

  8. The interannual variability of the Haines Index over North America

    Science.gov (United States)

    Lejiang Yu; Shiyuan Zhong; Xindi Bian; Warren E. Heilman; Joseph J. Charney

    2013-01-01

    The Haines index (HI) is a fire-weather index that is widely used as an indicator of the potential for dry, low-static-stability air in the lower atmosphere to contribute to erratic fire behavior or large fire growth. This study examines the interannual variability of HI over North America and its relationship to indicators of large-scale circulation anomalies. The...

  9. The Luzula comosa complex (Luzula section Luzula, Juncaceae) in western North America

    Czech Academy of Sciences Publication Activity Database

    Zika, P. F.; Wilson, B. A.; Kirschner, Jan

    2015-01-01

    Roč. 192, č. 4 (2015), s. 201-229 ISSN 1179-3155 Institutional research plan: CEZ:AV0Z60050516 Institutional support: RVO:67985939 Keywords : Luzula * Pacific North America * taxonomy Subject RIV: EF - Botanics Impact factor: 1.087, year: 2015

  10. Emerald ash borer in North America: a research and regulatory challenge

    Science.gov (United States)

    David Cappaert; Deborah G. McCullough; Therese M. Poland; Nathan W. Siegert

    2005-01-01

    The saga of the emerald ash borer, Agrilus planipennis Fairmare (Coleoptera: Buprestidae), in North America began on 25 June 2002, when five entomologists representing Michigan State University (MSU), the Michigan Department of Natural Resources (MDNR), and the U.S. Department of Agriculture, Animal and Plant Health Inspection Service (USDA APHIS)...

  11. Size Scaling in Western North Atlantic Loggerhead Turtles Permits Extrapolation between Regions, but Not Life Stages.

    Science.gov (United States)

    Marn, Nina; Klanjscek, Tin; Stokes, Lesley; Jusup, Marko

    2015-01-01

    Sea turtles face threats globally and are protected by national and international laws. Allometry and scaling models greatly aid sea turtle conservation and research, and help to better understand the biology of sea turtles. Scaling, however, may differ between regions and/or life stages. We analyze differences between (i) two different regional subsets and (ii) three different life stage subsets of the western North Atlantic loggerhead turtles by comparing the relative growth of body width and depth in relation to body length, and discuss the implications. Results suggest that the differences between scaling relationships of different regional subsets are negligible, and models fitted on data from one region of the western North Atlantic can safely be used on data for the same life stage from another North Atlantic region. On the other hand, using models fitted on data for one life stage to describe other life stages is not recommended if accuracy is of paramount importance. In particular, young loggerhead turtles that have not recruited to neritic habitats should be studied and modeled separately whenever practical, while neritic juveniles and adults can be modeled together as one group. Even though morphometric scaling varies among life stages, a common model for all life stages can be used as a general description of scaling, and assuming isometric growth as a simplification is justified. In addition to linear models traditionally used for scaling on log-log axes, we test the performance of a saturating (curvilinear) model. The saturating model is statistically preferred in some cases, but the accuracy gained by the saturating model is marginal.

  12. Comparisons of Box Model Calculations and Measurements of Formaldehyde from the 1997 North Atlantic Regional Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Frost, G. J.; Fried, Alan; Lee, Y.- N.; Wert, B.; Henry, B.; Drummond, J. R.; Evans, M. J.; Fehsenfeld, Fred C.; Goldan, P. D.; Holloway, J. S.; Hubler, Gerhard F.; Jakoubek, R.; Jobson, B Tom T.; Knapp, K.; Kuster, W. C.; Roberts, J.; Rudolph, Jochen; Ryerson, T. B.; Stohl, A.; Stroud, C.; Sueper, D. T.; Trainer, Michael; Williams, J.

    2002-04-18

    Formaldehyde (CH2O) measurements from two independent instruments are compared with photochemical box model calculations. The measurements were made on the National Oceanic and Atmospheric Administration P-3 aircraft as part of the 1997 North Atlantic Regional Experiment (NARE 97). The data set considered here consists of air masses sampled between 0 and 8 km over the North Atlantic Ocean which do not show recent influence from emissions or transport. These air masses therefore should be in photochemical steady state with respect to CH2O when constrained by the other P-3 measurements, and methane oxidation was expected to be the predominant source of CH2O in these air masses. For this data set both instruments measured identical CH2O concentrations to within 40 parts per trillion by volume (pptv) on average over the 0–800 pptv range, although differences larger than the combined 2s total uncertainty estimates were observed between the two instruments in 11% of the data. Both instruments produced higher CH2O concentrations than the model in more than 90% of this data set, with a median measured-modeled [CH2O] difference of 0.13 or 0.18 ppbv (depending on the instrument), or about a factor of 2. Such large differences cannot be accounted for by varying model input parameters within their respective uncertainty ranges. After examining the possible reasons for the model-measurement discrepancy, we conclude that there are probably one or more additional unknown sources of CH2O in the North Atlantic troposphere.

  13. Evaluation of the Atlantic Multidecadal Oscillation Impact on Large-Scale Atmospheric Circulation in the Atlantic Region in Summer

    Science.gov (United States)

    Semenov, V. A.; Cherenkova, E. A.

    2018-02-01

    The influence of the Atlantic Multidecadal Oscillation (AMO) on large-scale atmospheric circulation in the Atlantic region in summer for the period of 1950-2015 is investigated. It is shown that the intensification of the summer North Atlantic Oscillation (NAO) with significant changes in sea level pressure anomalies in the main centers of action (over Greenland and the British Isles) occurred while the North Atlantic was cooler. Sea surface temperature anomalies, which are linked to the AMO in the summer season, affect both the NAO index and fluctuations of the Eastern Atlantic/Western Russia (EAWR) centers of action. The positive (negative) phase of the AMO is characterized by a combination of negative (positive) values of the NAO and EAWR indices. The dominance of the opposite phases of the teleconnection indices in summer during the warm North Atlantic and in its colder period resulted in differences in the regional climate in Europe.

  14. Stranieri e vicini: le banche attraverso le frontiere del nord America. (Strangers and neighbours: cross-border banking in North America

    Directory of Open Access Journals (Sweden)

    J.W. DEAN

    2013-12-01

    Full Text Available L'articolo si occupa di aspetti normativi e competitivi della penetrazione reciproca da parte delle banche canadesi e statunitensi nei rispettivi mercati nazionali . Gli autori valutano il grado in cui i fattori economici sono gli unici responsabili per la differenza nei tassi di crescita tra le banche nazionali ed estere in Nord America. Essi sostengono che il regolamento non ha inciso sullala crescita delle banche estere in Nord America affrontando la questione della reciprocità in regolamenti bancari , prima di esaminare le banche estere negli Stati Uniti e il modo in cui sono state regolamentate .The paper is concerned with regulatory and competitive aspects of the mutual penetration by Canadian and U.S. banks of each other’s domestic markets. The authors assess the degree to which economic factors alone are responsible for the difference in growth rates between domestic and foreign banks in North America. They argue that regulation has not affected the growth of foreign banks in North America by addressing the question of reciprocity in banking regulations, before examining foreign banks in the U.S. and the manner in which they have been regulated. U.S. banks operating in Canada are then dealt with. Finally, the results of an empirical test of the proposition that the growth of cross-border banking is attributable to factors other than differential regulation is presented.JEL: G21

  15. Sommelier Suggestions: The Arthroscopy Association of North America Annual Meeting Inspires a Content Collection Worth Tasting.

    Science.gov (United States)

    Hunt, Timothy J; Brand, Jefferson C; Provencher, Matthew T; Rossi, Michael J; Lubowitz, James H

    2017-05-01

    The 2017 Arthroscopy Association of North America Annual Meeting Program inspires a Content Collection of Arthroscopy journal articles worthy of review. A foundation of a credible podium presentation is the published medical literature. Your Editors thus suggest recent publications that seem particularly relevant in the context of the 2017 annual meeting. Consider these articles as one would a suggestion for a good glass of wine to complement a delicious meal. Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  16. South Atlantic circulation in a world ocean model

    Directory of Open Access Journals (Sweden)

    M. H. England

    1994-08-01

    Full Text Available The circulation in the South Atlantic Ocean has been simulated within a global ocean general circulation model. Preliminary analysis of the modelled ocean circulation in the region indicates a rather close agreement of the simulated upper ocean flows with conventional notions of the large-scale geostrophic currents in the region. The modelled South Atlantic Ocean witnesses the return flow and export of North Atlantic Deep Water (NADW at its northern boundary, the inflow of a rather barotropic Antarctic Circumpolar Current (ACC through the Drake Passage, and the inflow of warm saline Agulhas water around the Cape of Good Hope. The Agulhas leakage amounts to 8.7 Sv, within recent estimates of the mass transport shed westward at the Agulhas retroflection. Topographic steering of the ACC dominates the structure of flow in the circumpolar ocean. The Benguela Current is seen to be fed by a mixture of saline Indian Ocean water (originating from the Agulhas Current and fresher Subantarctic surface water (originating in the ACC. The Benguela Current is seen to modify its flow and fate with depth; near the surface it flows north-westwards bifurcating most of its transport northward into the North Atlantic Ocean (for ultimate replacement of North Atlantic surface waters lost to the NADW conveyor. Deeper in the water column, more of the Benguela Current is destined to return with the Brazil Current, though northward flows are still generated where the Benguela Current extension encounters the coast of South America. At intermediate levels, these northward currents trace the flow of Antarctic Intermediate Water (AAIW equatorward, though even more AAIW is seen to recirculate poleward in the subtropical gyre. In spite of the model's rather coarse resolution, some subtle features of the Brazil-Malvinas Confluence are simulated rather well, including the latitude at which the two currents meet. Conceptual diagrams of the recirculation and interocean exchange of

  17. South Atlantic circulation in a world ocean model

    Directory of Open Access Journals (Sweden)

    Matthew H. England

    Full Text Available The circulation in the South Atlantic Ocean has been simulated within a global ocean general circulation model. Preliminary analysis of the modelled ocean circulation in the region indicates a rather close agreement of the simulated upper ocean flows with conventional notions of the large-scale geostrophic currents in the region. The modelled South Atlantic Ocean witnesses the return flow and export of North Atlantic Deep Water (NADW at its northern boundary, the inflow of a rather barotropic Antarctic Circumpolar Current (ACC through the Drake Passage, and the inflow of warm saline Agulhas water around the Cape of Good Hope. The Agulhas leakage amounts to 8.7 Sv, within recent estimates of the mass transport shed westward at the Agulhas retroflection. Topographic steering of the ACC dominates the structure of flow in the circumpolar ocean. The Benguela Current is seen to be fed by a mixture of saline Indian Ocean water (originating from the Agulhas Current and fresher Subantarctic surface water (originating in the ACC. The Benguela Current is seen to modify its flow and fate with depth; near the surface it flows north-westwards bifurcating most of its transport northward into the North Atlantic Ocean (for ultimate replacement of North Atlantic surface waters lost to the NADW conveyor. Deeper in the water column, more of the Benguela Current is destined to return with the Brazil Current, though northward flows are still generated where the Benguela Current extension encounters the coast of South America. At intermediate levels, these northward currents trace the flow of Antarctic Intermediate Water (AAIW equatorward, though even more AAIW is seen to recirculate poleward in the subtropical gyre. In spite of the model's rather coarse resolution, some subtle features of the Brazil-Malvinas Confluence are simulated rather well, including the latitude at which the two currents meet. Conceptual diagrams of the recirculation and interocean

  18. Simulated bat populations erode when exposed to climate change projections for western North America.

    Directory of Open Access Journals (Sweden)

    Mark A Hayes

    Full Text Available Recent research has demonstrated that temperature and precipitation conditions correlate with successful reproduction in some insectivorous bat species that live in arid and semiarid regions, and that hot and dry conditions correlate with reduced lactation and reproductive output by females of some species. However, the potential long-term impacts of climate-induced reproductive declines on bat populations in western North America are not well understood. We combined results from long-term field monitoring and experiments in our study area with information on vital rates to develop stochastic age-structured population dynamics models and analyzed how simulated fringed myotis (Myotis thysanodes populations changed under projected future climate conditions in our study area near Boulder, Colorado (Boulder Models and throughout western North America (General Models. Each simulation consisted of an initial population of 2,000 females and an approximately stable age distribution at the beginning of the simulation. We allowed each population to be influenced by the mean annual temperature and annual precipitation for our study area and a generalized range-wide model projected through year 2086, for each of four carbon emission scenarios (representative concentration pathways RCP2.6, RCP4.5, RCP6.0, RCP8.5. Each population simulation was repeated 10,000 times. Of the 8 Boulder Model simulations, 1 increased (+29.10%, 3 stayed approximately stable (+2.45%, +0.05%, -0.03%, and 4 simulations decreased substantially (-44.10%, -44.70%, -44.95%, -78.85%. All General Model simulations for western North America decreased by >90% (-93.75%, -96.70%, -96.70%, -98.75%. These results suggest that a changing climate in western North America has the potential to quickly erode some forest bat populations including species of conservation concern, such as fringed myotis.

  19. The Once and Future North Atlantic: How the Mid-Pliocene Warm Period Can Increase Stakeholder Preparedness in a Warming World

    Science.gov (United States)

    Jacobs, P.; de Mutsert, K.

    2013-12-01

    Paleoclimatic reconstructions, particularly from periods that may serve as an analog to the present and future greenhouse-driven warming, are increasingly being used to validate climate models as well as to provide constraints on broad impacts such as global temperature and sea level change. However, paleoclimatic data remains under-utilized in decision-making processes by stakeholders, who typically rely on scenarios produced by computer models or naive extrapolation of present trends. We hope to increase the information available to stakeholders by incorporating paleoclimatic data from the mid-Pliocene Warm Period (mPWP, ~3ma) into a fisheries model of the North Atlantic. North Atlantic fisheries are economically important and are expected to be sensitive to climatic change. State of the art climate models remain unable to realistically simulate the North Atlantic, both over the observational record as well as during times in the geologic past such as the mPWP. Given that the mPWP shares many of the same boundary conditions as those likely to be seen in the near future, we seek to answer the question 'What if the climate of the future looks more like the climate of the past?' relative to what state of the art computer models currently project. To that end we have created a suite of future North Atlantic Ocean scenarios using output from the CMIP3 and CMIP5 modeling experiments, as well as the PRISM group's Mid-Pliocene ocean reconstruction. We use these scenarios to drive an ecosystem-based fisheries model using the Ecopath with Ecosim (EwE) software to identify differences between the scenarios as the North Atlantic Ocean changes through time. Additionally, we examine the spatial component of these differences by using the Ecospace module of EwE. Whereas the Ecosim realizations are intended to capture the dynamic response to changing oceanographic parameters (SST, SSS, DO) over time, the Ecospace experiments are intended to explore the impact of different

  20. Consumer interest in social sustainability issues of whitefish from capture fisheries in the north-east Atlantic

    NARCIS (Netherlands)

    Veldhuizen, Linda J.L.; Lans, van der Ivo A.; Berentsen, Paul B.M.; Boer, de Imke J.M.; Bokkers, Eddy

    2017-01-01

    Capture fisheries in the north-east Atlantic account for approximately 10% of all fish consumed from capture fisheries globally. The literature shows that consumers show considerable interest in social sustainability of products in general and of fish specifically. This interest, however, has not

  1. Valuable biomolecules from nine North Atlantic red macroalgae: Amino acids, fatty acids, carotenoids, minerals and metals

    DEFF Research Database (Denmark)

    Razi Parjikolaei, Behnaz; Bruhn, Annette; Eybye, Karin Loft

    2016-01-01

    In modern society, novel marine resources are scrutinized pursuing compounds of use in the medical, pharmaceutical, biotech, food or feed industry. Few of the numerous marine macroalgae are currently exploited. In this study, the contents of nutritional compounds from nine common North Atlantic r...

  2. Response of the North Atlantic surface and intermediate ocean structure to climate warming of MIS 11.

    Science.gov (United States)

    Kandiano, Evgenia S; van der Meer, Marcel T J; Schouten, Stefan; Fahl, Kirsten; Sinninghe Damsté, Jaap S; Bauch, Henning A

    2017-04-10

    Investigating past interglacial climates not only help to understand how the climate system operates in general, it also forms a vital basis for climate predictions. We reconstructed vertical stratification changes in temperature and salinity in the North Atlantic for a period some 400 ka ago (MIS11), an interglacial time analogue of a future climate. As inferred from a unique set of biogeochemical, geochemical, and faunal data, the internal upper ocean stratification across MIS 11 shows distinct depth-dependent dynamical changes related to vertical as well as lateral shifts in the upper Atlantic meridional circulation system. Importantly, transient cold events are recognized near the end of the long phase of postglacial warming at surface, subsurface, mid, and deeper water layers. These data demonstrate that MIS 11 coolings over the North Atlantic were initially triggered by freshwater input at the surface and expansion of cold polar waters into the Subpolar Gyre. The cooling signal was then transmitted downwards into mid-water depths. Since the cold events occurred after the main deglacial phase we suggest that their cause might be related to continuous melting of the Greenland ice sheet, a mechanism that might also be relevant for the present and upcoming climate.

  3. SPURS: Salinity Processes in the Upper-Ocean Regional Study: THE NORTH ATLANTIC EXPERIMENT

    Science.gov (United States)

    Lindstrom, Eric; Bryan, Frank; Schmitt, Ray

    2015-01-01

    In this special issue of Oceanography, we explore the results of SPURS-1, the first part of the ocean process study Salinity Processes in the Upper-ocean Regional Study (SPURS). The experiment was conducted between August 2012 and October 2013 in the subtropical North Atlantic and was the first of two experiments (SPURS come in pairs!). SPURS-2 is planned for 20162017 in the tropical eastern Pacific Ocean.

  4. Conservation of native Pacific trout diversity in western North America

    Science.gov (United States)

    Penaluna, Brooke E.; Abadía-Cardoso, Alicia; Dunham, Jason B.; García de León, Francisco J; Gresswell, Robert E.; Luna, Arturo Ruiz; Taylor, Eric B.; Shepard, Bradley B.; Al-Chokhachy, Robert K.; Muhlfeld, Clint C.; Bestgen, Kevin R.; Rogers, Kevin H.; Escalante, Marco A; Keeley, Ernest R; Temple, Gabriel; Williams, Jack E.; Matthews, Kathleen; Pierce, Ron; Mayden, Richard L.; Kovach, Ryan; Garza, John Carlos; Fausch, Kurt D.

    2016-01-01

    Pacific trout Oncorhynchus spp. in western North America are strongly valued in ecological, socioeconomic, and cultural views, and have been the subject of substantial research and conservation efforts. Despite this, the understanding of their evolutionary histories, overall diversity, and challenges to their conservation is incomplete. We review the state of knowledge on these important issues, focusing on Pacific trout in the genus Oncorhynchus. Although most research on salmonid fishes emphasizes Pacific salmon, we focus on Pacific trout because they share a common evolutionary history, and many taxa in western North America have not been formally described, particularly in the southern extent of their ranges. Research in recent decades has led to the revision of many hypotheses concerning the origin and diversification of Pacific trout throughout their range. Although there has been significant success at addressing past threats to Pacific trout, contemporary and future threats represented by nonnative species, land and water use activities, and climate change pose challenges and uncertainties. Ultimately, conservation of Pacific trout depends on how well these issues are understood and addressed, and on solutions that allow these species to coexist with a growing scope of human influences.

  5. Multidecadal Increase in North Atlantic Coccolithophores and Potential Role of Increasing CO2

    Science.gov (United States)

    Rivero-Calle, S.; Gnanadesikan, A.; del Castillo, C. E.; Balch, W. M.; Guikema, S.

    2016-02-01

    As anthropogenic CO2 emissions acidify the oceans, calcifiers are expected to be negatively impacted. Using data from the Continuous Plankton Recorder, we show that coccolithophore occurrence in the North Atlantic has increased from 2 to over 20% from 1965 through 2010. We used Random Forest models to examine more than 20 possible environmental drivers of this change. CO2 and the Atlantic Multidecadal Oscillation were the best predictors. Since coccolithophore photosynthesis is strongly carbon-limited, we hypothesize that higher CO2 levels might be encouraging growth. A compilation of 41 independent laboratory studies supports our hypothesis. Our study shows a long-term basin-scale increase in coccolithophores and suggests that increasing pCO2 and temperature accelerated the growth rate of a key phytoplankton group for carbon cycling.

  6. Impacts of radiation management techniques on the North Atlantic Oscillation

    Science.gov (United States)

    Adakudlu, Muralidhar; Helge Otterå, Odd; Tjiputra, Jerry; Muri, Helene; Grini, Alf; Schulz, Michael

    2017-04-01

    The effectiveness of various climate engineering techniques in limiting the global warming signal to reasonable levels has been the topic of state-of-the-art research on climate change. Using an Earth system model, we show that these techniques have the potential to bring down the high CO2 concentration climate in RCP8.5 to a moderate climate similar to RCP4.5 in terms of global temperature. Nevertheless, their influence on the regional aspects of atmospheric circulation is not clear. The regional circulation patterns in the atmosphere are largely characterized by the natural variability modes, such as the North Atlantic Oscillation (NAO). In this study, we assess the impacts of three radiation managment techniques, namely, Stratospheric Aerosol Injection (SAI), Marine Sky Brightening (MSB) and Cirrus Cloud Thinning (CCT), on the structure and features of the NAO. The results indicate an east-northeastward shift as well as intensification of the NAO spatial pattern in the global warming scenarios of RCP4.5 and RCP8.5, with the signal being most intense in the latter. The climate engineering forcings when applied to the RCP8.5 case tend to reduce the strength of the NAO with little impact on its position. The CCT case appears to have the maximum effect on the NAO signal. The patterns of cloud radiative forcing, expressed as the difference between net radiative forcing at TOA under average conditions and clear sky conditions, reveal a northeastward shift of the radiative heating in the north Atlantic region. This implies a possible link between the changes in the NAO signal and the cloud radiative forcing.

  7. Stephanospora michoacanensis (Stephanosporaceae, Agaricales), a novel sequestrate truffle from North America

    Science.gov (United States)

    Gonzalo Guevara-Guerrero; Ivone Baez-Alvarado; Victor M. Gomez-Reyes; Michael Castellano

    2015-01-01

    Stephanospora michoacanensis is presented as a new species from North America. This angiocarpic species is recognized by its yellowcream peridial surface color, and broadly ellipsoid to subglobose, spiny or crested, inamyloid spores with a distinct, complete or nearly complete corona at its base. Stephanospora michoacanensis is similar to S. caroticolor, but S....

  8. Episodes of aeolian sand movement on a large spit system (Skagen Odde, Denmark) and North Atlantic storminess during the Little Ice Age

    DEFF Research Database (Denmark)

    Clemmensen, Lars B.; Glad, Aslaug C.; Hansen, Kristian W. T.

    2015-01-01

    . A change in the atmospheric circulation, so that both the North Atlantic Oscillation (NAO) and the Atlantic Multidecadal Oscillation (AMO) were negative, apparently led to an increased number of intense cyclones causing inland sand movement and dune building. The second and third phase of aeolian sand...

  9. A comparison of climatological subseasonal variations in the wintertime storm track activity between the North Pacific and Atlantic: local energetics and moisture effect

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sun-Seon; Ha, Kyung-Ja [Pusan National University, Division of Earth Environmental System, Busan (Korea, Republic of); Lee, June-Yi; Wang, Bin; Jin, Fei-Fei [University of Hawaii, School of Ocean and Earth Science and Technology, Honolulu, HI (United States); Lee, Woo-Jin [Korea Meteorological Administration, Seoul (Korea, Republic of)

    2011-12-15

    Distinct differences of the storm track-jet relationship over the North Pacific and North Atlantic are investigated in terms of barotropic and baroclinic energetics using NCEP-2 reanalysis data for the period of 1979-2008. From fall to midwinter the Pacific storm track (PST) activity weakens following the southward shift of the Pacific jet, whereas the Atlantic storm track (AST) activity remains steady in position and intensifies regardless of the slight southward shift of the Atlantic jet. This study is devoted to seeking for the factors that can contribute to this conspicuous difference between the two storm tracks on climatological subseasonal variation by analyzing eddy properties and local energetics. Different eddy properties over the two oceans lead to different contribution of barotropic energy conversion to the initiation of storm tracks. In the North Atlantic, meridionally elongated eddies gain kinetic energy efficiently from stretching deformation of the mean flow in the jet entrance. On the other hand, the term associated with shearing deformation is important for the initiation of PST. Analysis of baroclinic energetics reveals that the intensification of the AST activity in midwinter is mainly attributed to coincidence between location of maximum poleward and upward eddy heat fluxes and that of the largest meridional temperature gradient over slight upstream of the AST. The relatively large amount of precipitable water and meridional eddy moisture flux along baroclinic energy conversion axis likely provides a more favorable environment for baroclinic eddy growth over the North Atlantic than over the North Pacific. In the meantime, the midwinter minimum of the PST activity is attributable to the southward shift of the Pacific jet stream that leads to discrepancy between core region of poleward and upward heat fluxes and that of meridional thermal gradient. Weakening of eddy-mean flow interaction due to eddy shape and reduction of moist effect are also

  10. Dynamical attribution of oceanic prediction uncertainty in the North Atlantic: application to the design of optimal monitoring systems

    Science.gov (United States)

    Sévellec, Florian; Dijkstra, Henk A.; Drijfhout, Sybren S.; Germe, Agathe

    2017-11-01

    In this study, the relation between two approaches to assess the ocean predictability on interannual to decadal time scales is investigated. The first pragmatic approach consists of sampling the initial condition uncertainty and assess the predictability through the divergence of this ensemble in time. The second approach is provided by a theoretical framework to determine error growth by estimating optimal linear growing modes. In this paper, it is shown that under the assumption of linearized dynamics and normal distributions of the uncertainty, the exact quantitative spread of ensemble can be determined from the theoretical framework. This spread is at least an order of magnitude less expensive to compute than the approximate solution given by the pragmatic approach. This result is applied to a state-of-the-art Ocean General Circulation Model to assess the predictability in the North Atlantic of four typical oceanic metrics: the strength of the Atlantic Meridional Overturning Circulation (AMOC), the intensity of its heat transport, the two-dimensional spatially-averaged Sea Surface Temperature (SST) over the North Atlantic, and the three-dimensional spatially-averaged temperature in the North Atlantic. For all tested metrics, except for SST, ˜ 75% of the total uncertainty on interannual time scales can be attributed to oceanic initial condition uncertainty rather than atmospheric stochastic forcing. The theoretical method also provide the sensitivity pattern to the initial condition uncertainty, allowing for targeted measurements to improve the skill of the prediction. It is suggested that a relatively small fleet of several autonomous underwater vehicles can reduce the uncertainty in AMOC strength prediction by 70% for 1-5 years lead times.

  11. Conservation and sustainable use of medicinal and aromatic products in North America: Are there really lessons to be learned?

    Science.gov (United States)

    A. L. Hammett; James L. Chamberlain

    2002-01-01

    This paper discusses the legacy of nontimber forest products (NTFPs) and, more specifically, medicinal plant use in North America. It also discusses briefly MAP markets both in North America and throughout the world, and describes the constraints to the sustainable use and development of MAP resources. Lastly, the paper relates some lessons that may be appropriate for...

  12. Millennial-scale variability during the last glacial in vegetation records from North America

    Science.gov (United States)

    Jiménez-Moreno, Gonzalo; Anderson, R. Scott; Desprat, S.; Grigg, L.D.; Grimm, E.C.; Heusser, L.E.; Jacobs, Brian F.; Lopez-Martinez, C.; Whitlock, C.L.; Willard, D.A.

    2010-01-01

    High-resolution pollen records from North America show that terrestrial environments were affected by Dansgaard-Oeschger (D-O) and Heinrich climate variability during the last glacial. In the western, more mountainous regions, these climate changes are generally observed in the pollen records as altitudinal movements of climate-sensitive plant species, whereas in the southeast, they are recorded as latitudinal shifts in vegetation. Heinrich (HS) and Greenland (GS) stadials are generally correlated with cold and dry climate and Greenland interstadials (GI) with warm-wet phases. The pollen records from North America confirm that vegetation responds rapidly to millennial-scale climate variability, although the difficulties in establishing independent age models for the pollen records make determination of the absolute phasing of the records to surface temperatures in Greenland somewhat uncertain. ?? 2009 Elsevier Ltd.

  13. Wild bird surveillance for highly pathogenic avian influenza H5 in North America

    Science.gov (United States)

    Flint, Paul L.; Pearce, John M.; Franson, J. Christian; Derksen, Dirk V.

    2015-01-01

    It is unknown how the current Asian origin highly pathogenic avian influenza H5 viruses arrived, but these viruses are now poised to become endemic in North America. Wild birds harbor these viruses and have dispersed them at regional scales. What is unclear is how the viruses may be moving from the wild bird reservoir into poultry holdings. Active surveillance of live wild birds is likely the best way to determine the true distribution of these viruses. We also suggest that sampling be focused on regions with the greatest risk for poultry losses and attempt to define the mechanisms of transfer to enhance biosecurity. Responding to the recent outbreaks of highly pathogenic avian influenza in North America requires an efficient plan with clear objectives and potential management outcomes.

  14. Corallimorpharia collected during the CANCAP expeditions (1976-1986) in the south-eastern part of the North Atlantic*

    NARCIS (Netherlands)

    Hartog, den J.C.; Ocaña, O.; Brito, A.

    1993-01-01

    Species of Corallimorpharia collected during the CANCAP expeditions in the south-eastern part of the North Atlantic are described and discussed, altogether five species belonging to three genera of Corallimorphidae: the shallow water forms Corynactis viridis Allman, 1846, Pseudocorynactis

  15. Distribution and abundance of fin whales (Balaenoptera physalus in the Northeast and Central Atlantic as inferred from the North Atlantic Sightings Surveys 1987-2001

    Directory of Open Access Journals (Sweden)

    Gísli A Víkingsson

    2013-10-01

    Full Text Available North Atlantic Sightings Surveys (NASS is a series of large scale international cetacean line transect surveys, conducted in 1987, 1989, 1995 and 2001, that covered a large part of the central and eastern North Atlantic. Target species were fin (Balaenoptera physalus, common minke (B. acutorostrata, pilot (Globicephala melas and sei (B. borealis whales. Here we present new estimates of abundance for fin whales from the 2 most recent surveys and analysis of trends throughout the survey period. Fin whales were found in highest densities in the Irminger Sea between Iceland and Greenland. Abundance of fin whales in the survey area of the Icelandic and Faroese vessels (Central North Atlantic was estimated as 19,672 (95% C.I. 12,083-28,986 animals in 1995 and 24,887 (95% C.I. 18,186-30,214 in 2001. The estimates are negatively biased because of whales diving during the passage of vessels, and whales being missed by observers, but these and other potential biases are likely small for this species. The abundance of fin whales increased significantly over the survey period. For all areas combined the estimated annual growth rate was 4%. An estimated annual increase of 10% in the area between Iceland and Greenland was responsible for most of this overall increase in numbers of fin whales in the area. Although high, the estimated rates of increase are not out of bounds of biological plausibility and can thus be viewed as recovery of a depleted population. However, the apparent pattern of population growth and the whaling history in the area indicate that fin whales made a significant recovery during the first half of the 20th century and that the recent observed high growth rates cannot be explained solely by recovery after overexploitation.

  16. Holocene North Atlantic Overturning in an atmosphere-ocean-sea-ice model compared to proxy-based reconstructions

    NARCIS (Netherlands)

    Blaschek, M.; Renssen, H.; Kissel, C.; Thornalley, D.

    2015-01-01

    Climate and ocean circulation in the North Atlantic region changed over the course of the Holocene, partly because of disintegrating ice sheets and partly because of an orbital-induced insolation trend. In the Nordic Seas, this impact was accompanied by a rather small, but significant, amount of

  17. Potential contribution of surface-dwelling Sargassum algae to deep-sea ecosystems in the southern North Atlantic

    Science.gov (United States)

    Baker, Philip; Minzlaff, Ulrike; Schoenle, Alexandra; Schwabe, Enrico; Hohlfeld, Manon; Jeuck, Alexandra; Brenke, Nils; Prausse, Dennis; Rothenbeck, Marcel; Brix, Saskia; Frutos, Inmaculada; Jörger, Katharina M.; Neusser, Timea P.; Koppelmann, Rolf; Devey, Colin; Brandt, Angelika; Arndt, Hartmut

    2018-02-01

    Deep-sea ecosystems, limited by their inability to use primary production as a source of carbon, rely on other sources to maintain life. Sedimentation of organic carbon into the deep sea has been previously studied, however, the high biomass of sedimented Sargassum algae discovered during the VEMA Transit expedition in 2014/2015 to the southern North Atlantic, and its potential as a regular carbon input, has been an underestimated phenomenon. To determine the potential for this carbon flux, a literature survey of previous studies that estimated the abundance of surface water Sargassum was conducted. We compared these estimates with quantitative analyses of sedimented Sargassum appearing on photos taken with an autonomous underwater vehicle (AUV) directly above the abyssal sediment during the expedition. Organismal communities associated to Sargassum fluitans from surface waters were investigated and Sargassum samples collected from surface waters and the deep sea were biochemically analyzed (fatty acids, stable isotopes, C:N ratios) to determine degradation potential and the trophic significance within deep-sea communities. The estimated Sargassum biomass (fresh weight) in the deep sea (0.07-3.75 g/m2) was several times higher than that estimated from surface waters in the North Atlantic (0.024-0.84 g/m2). Biochemical analysis showed degradation of Sargassum occurring during sedimentation or in the deep sea, however, fatty acid and stable isotope analysis did not indicate direct trophic interactions between the algae and benthic organisms. Thus, it is assumed that components of the deep-sea microbial food web form an important link between the macroalgae and larger benthic organisms. Evaluation of the epifauna showed a diverse nano- micro-, meio, and macrofauna on surface Sargassum and maybe transported across the Atlantic, but we had no evidence for a vertical exchange of fauna components. The large-scale sedimentation of Sargassum forms an important trophic link

  18. First report of Pineus strobi (Hartig) (Hemiptera: Adelgidae) in western North America

    Science.gov (United States)

    The pine bark adelgid, Pineus strobi (Hartig, 1839) (Hempitera: Adelgidae), is native to eastern North America. Its main host species is eastern white pine, Pinus strobus L. Pineus strobi is reported here for the first time from Washington, Colorado, Saskatchewan and tentatively Oregon by identifica...

  19. Temperature, salinity, and nutrients data from CTD and bottle casts in the Arctic, North Atlantic and North Pacific Oceans from multiple platforms from 1963-04-30 to 1999-02-15 (NODC Accession 0000418)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — CTD, bottle, and other data were collected from the Arctic Ocean, North Atlantic Ocean, and North Pacific from multiple platforms from 30 April 1963 to 15 February...

  20. Plastic ingestion in oceanic-stage loggerhead sea turtles (Caretta caretta) off the North Atlantic subtropical gyre.

    Science.gov (United States)

    Pham, Christopher K; Rodríguez, Yasmina; Dauphin, Axelle; Carriço, Rita; Frias, João P G L; Vandeperre, Frederic; Otero, Vanessa; Santos, Marco R; Martins, Helen R; Bolten, Alan B; Bjorndal, Karen A

    2017-08-15

    Juvenile oceanic-stage sea turtles are particularly vulnerable to the increasing quantity of plastic coming into the oceans. In this study, we analysed the gastrointestinal tracts of 24 juvenile oceanic-stage loggerheads (Caretta caretta) collected off the North Atlantic subtropical gyre, in the Azores region, a key feeding ground for juvenile loggerheads. Twenty individuals were found to have ingested marine debris (83%), composed exclusively of plastic items (primarily polyethylene and polypropylene) identified by μ-Fourier Transform Infrared Spectroscopy. Large microplastics (1-5mm) represented 25% of the total number of debris and were found in 58% of the individuals sampled. Average number of items was 15.83±6.09 (±SE) per individual, corresponding to a mean dry mass of 1.07±0.41g. The results of this study demonstrate that plastic pollution acts as another stressor for this critical life stage of loggerhead turtles in the North Atlantic. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Observed and modeled pathways of the Iceland Scotland Overflow Water in the eastern North Atlantic

    Science.gov (United States)

    Zou, Sijia; Lozier, Susan; Zenk, Walter; Bower, Amy; Johns, William

    2017-12-01

    The spreading of Iceland Scotland Overflow Water (ISOW) in the eastern North Atlantic has largely been studied in an Eulerian frame using numerical models or with observations limited to a few locations. No study to date has provided a comprehensive description of the ISOW spreading pathways from both Eulerian and Lagrangian perspectives. In this paper, we use a combination of previously unreported current meter data, hydrographic data, RAFOS float data, and a high resolution (1/12°) numerical ocean model to study the spreading pathways of ISOW from both of these perspectives. We identify three ISOW transport cores in the central Iceland Basin (∼59°N), with the major core along the eastern boundary of the Reykjanes Ridge (RR) and the other two in the basin interior. Based on trajectories of observed and/or numerical floats seeded along 59°N, we also describe the ISOW spreading pathways and quantify their relative importance. Within 10 years, 7-11% of ISOW from 59°N escapes into the Irminger Sea via gaps in the RR north of the Charlie Gibbs Fracture Zone (CGFZ); the water that moves through these gaps principally originates from the shallower ISOW layer along the RR eastern boundary. 10-13% travels further southward until the CGFZ, where it crosses westward into the western subpolar gyre. 18-21% of ISOW spreads southward along the eastern flank of the Mid-Atlantic Ridge into the Western European Basin (WEB). Most of the remaining water stays in the Iceland Basin over the 10-year period. A model-based investigation provides a first look at the temporal variability of these ISOW pathways. We find that the fraction of southward water exported into the WEB is anti-correlated with the export through the CGFZ, a result assumed to reflect these pathways' interactions with the North Atlantic Current in magnitude and/or position shift.

  2. Don't Miss the Meeting: Arthroscopy Association of North America Annual Scientific Meeting Reveals Timely and Unique Content.

    Science.gov (United States)

    Lubowitz, James H; Brand, Jefferson C; Provencher, Matthew T; Rossi, Michael J

    2017-04-01

    The Annual Meeting of the Arthroscopy Association of North America (AANA) is notable for timely presentation of innovative research and development. In addition, much of what is presented at the Annual Meeting is never published in Arthroscopy journal. Readers are encouraged to attend the AANA meeting to keep up with the discussion and debate. Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  3. Atlantic consumption of French rum and brandy and economic growth in the seventeenth- and eighteenth-century Caribbean.

    Science.gov (United States)

    Mandelblatt, Bertie

    2011-01-01

    Why did the production of rum in the French West Indies not achieve the same success within the French Atlantic as it did in the British Atlantic world? Surveying the history of rum production in the French Caribbean in the seventeenth and eighteenth centuries, this article contends that the reason why no regional trade in rum developed in French North America resulted from fierce industrial and institutional competition from brandy producers in metropolitan France. Rum, nevertheless, remained significant within the culture and economy of Native Americans and African Americans. This article seeks to add nuance to the wider debate of the ability of the trans-border diffusion of new ideas to stimulate and institutionalize industrial and economic growth in the Atlantic world. French entrepreneurs were no less ‘entrepreneurial’ than their British counterparts, but real constraints on consumption on both sides of the Atlantic created insufficient demand.

  4. A seesaw in Mediterranean precipitation during the Roman Period linked to millennial-scale changes in the North Atlantic

    Science.gov (United States)

    Dermody, B. J.; de Boer, H. J.; Bierkens, M. F. P.; Weber, S. L.; Wassen, M. J.; Dekker, S. C.

    2012-03-01

    We present a reconstruction of the change in climatic humidity around the Mediterranean between 3000-1000 yr BP. Using a range of proxy archives and model simulations we demonstrate that climate during this period was typified by a millennial-scale seesaw in climatic humidity between Spain and Israel on one side and the Central Mediterranean and Turkey on the other, similar to precipitation anomalies associated with the East Atlantic/West Russia pattern in current climate. We find that changes in the position and intensity of the jet stream indicated by our analysis correlate with millennial changes in North Atlantic sea surface temperature. A model simulation indicates the proxies of climatic humidity used in our analysis were unlikely to be influenced by climatic aridification caused by deforestation during the Roman Period. That finding is supported by an analysis of the distribution of archaeological sites in the Eastern Mediterranean which exhibits no evidence that human habitation distribution changed since ancient times as a result of climatic aridification. Therefore we conclude that changes in climatic humidity over the Mediterranean during the Roman Period were primarily caused by a modification of the jet stream linked to sea surface temperature change in the North Atlantic. Based on our findings, we propose that ocean-atmosphere coupling may have contributed to regulating Atlantic Meridional Overturning Circulation intensity during the period of analysis.

  5. Quinoa cultivation in western North America: lessons learned and the path forward

    Science.gov (United States)

    Quinoa (Chenopodium quinoa Willd) is a relatively new crop to farmers in North America; however recent interest in domestic cultivation of quinoa has skyrocketed due to a rapid, worldwide increase in demand for this nutritious and delicious Andean crop. Researchers at five western U.S. universities ...

  6. Modeling concentrations and fluxes of atmospheric CO2 in the North East Atlantic region

    DEFF Research Database (Denmark)

    Geels, C.; Christensen, J.H.; Hansen, A.W.

    2001-01-01

    As part of the Danish NEAREX project a three-dimensional Eulerian hemispheric air pollution model is used to study the transport and concentrations of atmospheric CO2 in the North East Atlantic region. The model domain covers the major part of the Northern Hemisphere and currently the model...

  7. Cucullia umbratica (Lepidoptera, Noctuidae, a new European noctuid in North America

    Directory of Open Access Journals (Sweden)

    Louis Handfield

    2010-03-01

    Full Text Available The discovery of a noctuid new for North America, Cucullia umbratica (Linnaeus, 1758 (Lepidoptera: Noctuidae, is reported from the Magdalen Islands (Quebec, Canada. A male and a female from the Islands are illustrated as well as specimens of the superficially similar species Cucullia intermedia Speyer, 1870. The male genitalia of both species are illustrated.

  8. 77 FR 65150 - Cryovac North America; Withdrawal of Color Additive Petition

    Science.gov (United States)

    2012-10-25

    ... regulations be amended to provide for the safe use of synthetic iron oxide as a color additive in or on cooked... Exempt From Certification to provide for the safe use of synthetic iron oxide as a color additive in or.... FDA-2004-C-0559 (Formerly Docket No. 2004C[hyphen]0078)] Cryovac North America; Withdrawal of Color...

  9. Understanding the North Atlantic Oscillation and Its Effects in the Mediterranean

    Science.gov (United States)

    Trigo, Ricardo M.; Serrano, Sergio M. Vicente

    2010-11-01

    ESF-MedCLIVAR Workshop on Hydrological, Socioeconomic and Ecological Impacts of the North Atlantic Oscillation in the Mediterranean; Zaragoza, Spain, 24-27 May 2010; According to the latest Intergovernmental Panel on Climate Change report, the Mediterranean basin represents one of the most important hot spots of climate change in the world, with recent trends toward a hotter and drier climate being related to changes in atmospheric circulation patterns. Among these patterns the North Atlantic Oscillation (NAO) is the most important one and the only one that exerts a clear influence throughout the year, although with stronger intensity and extension during winter. In the framework of the European Science Foundation's Mediterranean Climate Variability and Predictability (MedCLIVAR) program (http://www.medclivar.eu/), a thematic workshop devoted to the hydrological, socioeconomic, and ecological impacts of the NAO in the Mediterranean area was held in Spain. The main objective of this 3-day workshop was to foster interaction in this increasingly interdisciplinary topic, in particular, among climatologists, hydrologists, geographers, agronomists, biologists, and other scientists. The workshop was attended by 62 participants from 15 different countries and included a mix of senior scientists and graduate students. The workshop was divided into five sessions focusing on (1) natural hazards, including droughts, severe precipitations, floods, heat waves, and cold spells; (2) vegetation activity and agriculture production; (3) natural ecosystems and environment, including forest dynamics, fisheries, dynamics of animal populations, and air quality; (4) geomorphology, including landslides and debris flows, erosivity mechanisms, and surface erosion processes; and (5) renewable energies production, including hydraulic, eolic, and solar.

  10. 78 FR 30963 - Michelin North America, Incorporated, Grant of Petition for Decision of Inconsequential...

    Science.gov (United States)

    2013-05-23

    ...: Michelin North America, Inc. (MNA), has determined that certain Michelin brand passenger car replacement... ETRTO standard and the Tire and Rim Association (T&RA) standard, thus becoming noncompliant with the...

  11. Size Scaling in Western North Atlantic Loggerhead Turtles Permits Extrapolation between Regions, but Not Life Stages.

    Directory of Open Access Journals (Sweden)

    Nina Marn

    Full Text Available Sea turtles face threats globally and are protected by national and international laws. Allometry and scaling models greatly aid sea turtle conservation and research, and help to better understand the biology of sea turtles. Scaling, however, may differ between regions and/or life stages. We analyze differences between (i two different regional subsets and (ii three different life stage subsets of the western North Atlantic loggerhead turtles by comparing the relative growth of body width and depth in relation to body length, and discuss the implications.Results suggest that the differences between scaling relationships of different regional subsets are negligible, and models fitted on data from one region of the western North Atlantic can safely be used on data for the same life stage from another North Atlantic region. On the other hand, using models fitted on data for one life stage to describe other life stages is not recommended if accuracy is of paramount importance. In particular, young loggerhead turtles that have not recruited to neritic habitats should be studied and modeled separately whenever practical, while neritic juveniles and adults can be modeled together as one group. Even though morphometric scaling varies among life stages, a common model for all life stages can be used as a general description of scaling, and assuming isometric growth as a simplification is justified. In addition to linear models traditionally used for scaling on log-log axes, we test the performance of a saturating (curvilinear model. The saturating model is statistically preferred in some cases, but the accuracy gained by the saturating model is marginal.

  12. Mass Wasting during the Cretaceous/Tertiary Transition in the North Atlantic: Relationship to the Chicxulub Impact?

    Science.gov (United States)

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

    2015-04-01

    Deep-sea sections in the North Atlantic are claimed to contain the most complete sedimentary records and ultimate proof that the Chicxulub impact is Cretaceous-Tertiary boundary (KTB) in age and caused the mass extinction. A multi-disciplinary study of North Atlantic DSDP Sites 384, 386 and 398, based on high-resolution planktonic foraminiferal biostratigraphy, carbon and oxygen stable isotopes, clay and whole-rock mineralogy and granulometry, reveals the age, stratigraphic completeness and nature of sedimentary disturbances. Results show a major KTB hiatus at Site 384 with zones CF1, P0 and P1a missing, spanning at least ~540 ky, similar to other North Atlantic and Caribbean localities associated with tectonic activity and Gulf Stream erosion. At Sites 386 and 398, discrete intervals of disturbed sediments with mm-to-cm-thick spherule layers have previously been interpreted as KTB age impact-generated earthquakes destabilizing continental margins prior to settling of impact spherules. However, improved age control based on planktonic foraminifera indicates deposition in the early Danian zone P1a(2) (upper Parvularugoglobigerina eugubina zone) more than 100 ky after the KTB. At Site 386, two intervals of white chalk contain very small (winnowing via distal turbidites. At Site 398, convoluted red to tan sediments with early Danian and reworked Cretaceous species represent slumping of shallow water sediments as suggested by dominance of mica and low smectite compared to in situ deposition. We conclude that mass wasting was likely the result of earthquakes associated with increased tectonic activity in the Caribbean and the Iberian Peninsula during the early Danian well after the Chicxulub impact.

  13. The Population Consequences of Disturbance Model Application to North Atlantic Right Whales (Eubalaena glacialis)

    Science.gov (United States)

    2015-09-30

    physiology, and the revised approach is called PCOD (Population Consequences Of Disturbance). In North Atlantic right whales (Eubalaena glacialis...acoustic disturbance and prey variability into the PCOD model. OBJECTIVES The objectives for this study are to: 1) develop a Hierarchical...the model to assessing the effects of acoustics on the population. We have refined and applied the PCOD model developed for right whales (Schick et

  14. Production and degradation of fluorescent dissolved organic matter in surface waters of the eastern north Atlantic ocean

    NARCIS (Netherlands)

    Lønborg, C.; Yokokawa, T.; Herndl, G.J.; Alvarez-Salgado, X.A.

    2015-01-01

    The distribution and fate of coloured dissolved organic matter (CDOM) in the epipelagic Eastern North Atlantic was investigated during a cruise in the summer 2009 by combining field observations and culture experiments. Dissolved organic carbon (DOC) and nitrogen (DON), the absorption spectra of

  15. Water mass distributions and transports for the 2014 GEOVIDE cruise in the North Atlantic

    Directory of Open Access Journals (Sweden)

    M. I. García-Ibáñez

    2018-04-01

    Full Text Available We present the distribution of water masses along the GEOTRACES-GA01 section during the GEOVIDE cruise, which crossed the subpolar North Atlantic Ocean and the Labrador Sea in the summer of 2014. The water mass structure resulting from an extended optimum multiparameter (eOMP analysis provides the framework for interpreting the observed distributions of trace elements and their isotopes. Central Waters and Subpolar Mode Waters (SPMW dominated the upper part of the GEOTRACES-GA01 section. At intermediate depths, the dominant water mass was Labrador Sea Water, while the deep parts of the section were filled by Iceland–Scotland Overflow Water (ISOW and North-East Atlantic Deep Water. We also evaluate the water mass volume transports across the 2014 OVIDE line (Portugal to Greenland section by combining the water mass fractions resulting from the eOMP analysis with the absolute geostrophic velocity field estimated through a box inverse model. This allowed us to assess the relative contribution of each water mass to the transport across the section. Finally, we discuss the changes in the distribution and transport of water masses between the 2014 OVIDE line and the 2002–2010 mean state. At the upper and intermediate water levels, colder end-members of the water masses replaced the warmer ones in 2014 with respect to 2002–2010, in agreement with the long-term cooling of the North Atlantic Subpolar Gyre that started in the mid-2000s. Below 2000 dbar, ISOW increased its contribution in 2014 with respect to 2002–2010, with the increase being consistent with other estimates of ISOW transports along 58–59° N. We also observed an increase in SPMW in the East Greenland Irminger Current in 2014 with respect to 2002–2010, which supports the recent deep convection events in the Irminger Sea. From the assessment of the relative water mass contribution to the Atlantic Meridional Overturning Circulation (AMOC across the OVIDE line, we conclude

  16. Germanic heritage languages in North America: Acquisition, attrition and change

    OpenAIRE

    Johannessen, Janne Bondi; Salmons, Joseph C.; Westergaard, Marit; Anderssen, Merete; Arnbjörnsdóttir, Birna; Allen, Brent; Pierce, Marc; Boas, Hans C.; Roesch, Karen; Brown, Joshua R.; Putnam, Michael; Åfarli, Tor A.; Newman, Zelda Kahan; Annear, Lucas; Speth, Kristin

    2015-01-01

    This book presents new empirical findings about Germanic heritage varieties spoken in North America: Dutch, German, Pennsylvania Dutch, Icelandic, Norwegian, Swedish, West Frisian and Yiddish, and varieties of English spoken both by heritage speakers and in communities after language shift. The volume focuses on three critical issues underlying the notion of ‘heritage language’: acquisition, attrition and change. The book offers theoretically-informed discussions of heritage language processe...

  17. Multidecadal increase in North Atlantic coccolithophores and the potential role of rising CO₂.

    Science.gov (United States)

    Rivero-Calle, Sara; Gnanadesikan, Anand; Del Castillo, Carlos E; Balch, William M; Guikema, Seth D

    2015-12-18

    As anthropogenic carbon dioxide (CO2) emissions acidify the oceans, calcifiers generally are expected to be negatively affected. However, using data from the Continuous Plankton Recorder, we show that coccolithophore occurrence in the North Atlantic increased from ~2 to more than 20% from 1965 through 2010. We used random forest models to examine more than 20 possible environmental drivers of this change, finding that CO2 and the Atlantic Multidecadal Oscillation were the best predictors, leading us to hypothesize that higher CO2 levels might be encouraging growth. A compilation of 41 independent laboratory studies supports our hypothesis. Our study shows a long-term basin-scale increase in coccolithophores and suggests that increasing CO2 and temperature have accelerated the growth of a phytoplankton group that is important for carbon cycling. Copyright © 2015, American Association for the Advancement of Science.

  18. Causes and projections of abrupt climate-driven ecosystem shifts in the North Atlantic

    DEFF Research Database (Denmark)

    Beaugrand, G.; Edwards, M.; Brander, Keith

    2008-01-01

    Warming of the global climate is now unequivocal and its impact on Earth' functional units has become more apparent. Here, we show that marine ecosystems are not equally sensitive to climate change and reveal a critical thermal boundary where a small increase in temperature triggers abrupt...... ecosystem shifts seen across multiple trophic levels. This large-scale boundary is located in regions where abrupt ecosystem shifts have been reported in the North Atlantic sector and thereby allows us to link these shifts by a global common phenomenon. We show that these changes alter the biodiversity...... and carrying capacity of ecosystems and may, combined with fishing, precipitate the reduction of some stocks of Atlantic cod already severely impacted by exploitation. These findings offer a way to anticipate major ecosystem changes and to propose adaptive strategies for marine exploited resources such as cod...

  19. Korean older intimate partner violence survivors in North America: cultural considerations and practice recommendations.

    Science.gov (United States)

    Shim, Woochan S; Nelson-Becker, Holly

    2009-01-01

    While literature on elder abuse has expanded, elder abuse by intimate partners has been less investigated. Even less is known about intimate partner violence among older Koreans living in North America. This article identifies important cultural considerations for individuals helping the Korean older adult community, beginning with the definition of intimate partner violence in this community and barriers to leaving that include traditional views of the East Asian self. Current practice interventions are discussed and recommendations for future practice such as healing han, the accumulated suffering from years of abuse, are suggested. The ultimate goal of this paper is to expand awareness in order to develop the best culturally competent prevention and intervention practice for Korean older intimate partner violence survivors in North America.

  20. Bidecadal North Atlantic ocean circulation variability controlled by timing of volcanic eruptions.

    Science.gov (United States)

    Swingedouw, Didier; Ortega, Pablo; Mignot, Juliette; Guilyardi, Eric; Masson-Delmotte, Valérie; Butler, Paul G; Khodri, Myriam; Séférian, Roland

    2015-03-30

    While bidecadal climate variability has been evidenced in several North Atlantic paleoclimate records, its drivers remain poorly understood. Here we show that the subset of CMIP5 historical climate simulations that produce such bidecadal variability exhibits a robust synchronization, with a maximum in Atlantic Meridional Overturning Circulation (AMOC) 15 years after the 1963 Agung eruption. The mechanisms at play involve salinity advection from the Arctic and explain the timing of Great Salinity Anomalies observed in the 1970s and the 1990s. Simulations, as well as Greenland and Iceland paleoclimate records, indicate that coherent bidecadal cycles were excited following five Agung-like volcanic eruptions of the last millennium. Climate simulations and a conceptual model reveal that destructive interference caused by the Pinatubo 1991 eruption may have damped the observed decreasing trend of the AMOC in the 2000s. Our results imply a long-lasting climatic impact and predictability following the next Agung-like eruption.