Modeling North Atlantic Nor'easters With Modern Wave Forecast Models

Science.gov (United States)

Perrie, Will; Toulany, Bechara; Roland, Aron; Dutour-Sikiric, Mathieu; Chen, Changsheng; Beardsley, Robert C.; Qi, Jianhua; Hu, Yongcun; Casey, Michael P.; Shen, Hui

2018-01-01

Three state-of-the-art operational wave forecast model systems are implemented on fine-resolution grids for the Northwest Atlantic. These models are: (1) a composite model system consisting of SWAN implemented within WAVEWATCHIII® (the latter is hereafter, WW3) on a nested system of traditional structured grids, (2) an unstructured grid finite-volume wave model denoted "SWAVE," using SWAN physics, and (3) an unstructured grid finite element wind wave model denoted as "WWM" (for "wind wave model") which uses WW3 physics. Models are implemented on grid systems that include relatively large domains to capture the wave energy generated by the storms, as well as including fine-resolution nearshore regions of the southern Gulf of Maine with resolution on the scale of 25 m to simulate areas where inundation and coastal damage have occurred, due to the storms. Storm cases include three intense midlatitude cases: a spring Nor'easter storm in May 2005, the Patriot's Day storm in 2007, and the Boxing Day storm in 2010. Although these wave model systems have comparable overall properties in terms of their performance and skill, it is found that there are differences. Models that use more advanced physics, as presented in recent versions of WW3, tuned to regional characteristics, as in the Gulf of Maine and the Northwest Atlantic, can give enhanced results.

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

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

Atlantic City, New Jersey Tsunami Forecast Grids for MOST Model

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Atlantic City, New Jersey Forecast Model Grids provides bathymetric data strictly for tsunami inundation modeling with the Method of Splitting Tsunami (MOST)...

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

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°

An investigation of tropical Atlantic bias in a high-resolution coupled regional climate model

Energy Technology Data Exchange (ETDEWEB)

Patricola, Christina M.; Saravanan, R.; Hsieh, Jen-Shan [Texas A and M University, Department of Atmospheric Sciences, College Station, TX (United States); Li, Mingkui; Xu, Zhao [Texas A and M University, Department of Oceanography, College Station, TX (United States); Ocean University of China, Key Laboratory of Physical Oceanography of Ministry of Education, Qingdao (China); Chang, Ping [Texas A and M University, Department of Oceanography, College Station, TX (United States); Ocean University of China, Key Laboratory of Physical Oceanography of Ministry of Education, Qingdao (China); Second Institute of Oceanography, State Key Laboratory of Satellite Ocean Environment Dynamics, Hangzhou, Zhejiang (China)

2012-11-15

Coupled atmosphere-ocean general circulation models (AOGCMs) commonly fail to simulate the eastern equatorial Atlantic boreal summer cold tongue and produce a westerly equatorial trade wind bias. This tropical Atlantic bias problem is investigated with a high-resolution (27-km atmosphere represented by the Weather Research and Forecasting Model, 9-km ocean represented by the Regional Ocean Modeling System) coupled regional climate model. Uncoupled atmospheric simulations test climate sensitivity to cumulus, land-surface, planetary boundary layer, microphysics, and radiation parameterizations and reveal that the radiation scheme has a pronounced impact in the tropical Atlantic. The CAM radiation simulates a dry precipitation (up to -90%) and cold land-surface temperature (up to -8 K) bias over the Amazon related to an over-representation of low-level clouds and almost basin-wide westerly trade wind bias. The Rapid Radiative Transfer Model and Goddard radiation simulates doubled Amazon and Congo Basin precipitation rates and a weak eastern Atlantic trade wind bias. Season-long high-resolution coupled regional model experiments indicate that the initiation of the warm eastern equatorial Atlantic sea surface temperature (SST) bias is more sensitive to the local rather than basin-wide trade wind bias and to a wet Congo Basin instead of dry Amazon - which differs from AOGCM simulations. Comparisons between coupled and uncoupled simulations suggest a regional Bjerknes feedback confined to the eastern equatorial Atlantic amplifies the initial SST, wind, and deepened thermocline bias, while barrier layer feedbacks are relatively unimportant. The SST bias in some CRCM simulations resembles the typical AOGCM bias indicating that increasing resolution is unlikely a simple solution to this problem. (orig.)

76 FR 13583 - Atlantic Highly Migratory Species; Atlantic Bluefin Tuna Quotas and Atlantic Tuna Fisheries...

Science.gov (United States)

2011-03-14

... address concerns raised in a recent decision by a NOAA Administrative Law Judge (see Atlantic Tunas Transfer at Sea section for case reference). NMFS has prepared a draft Environmental Assessment (EA... subtraction of these allocations directly from the TAC, the recommendation allocates the remainder to the UK...

Atlantic multidecadal oceanic variability and its influence on the atmosphere in a climate model

Energy Technology Data Exchange (ETDEWEB)

Msadek, Rym; Frankignoul, Claude [Universite Pierre et Marie Curie, Paris 6, LOCEAN/IPSL, Paris (France)

2009-07-15

The mechanisms controlling the decadal to multidecadal variability of the Atlantic Meridional Overturning Circulation (MOC) and its influence on the atmosphere are investigated using a control simulation with the IPSL-CM4 climate model. The multidecadal fluctuations of the MOC are mostly driven by deep convection in the subpolar gyre, which occurs south of Iceland in the model. The latter is primarily influenced by the anomalous advection of salinity due to changes in the East Atlantic Pattern (EAP), which is the second mode of atmospheric variability in the North Atlantic region. The North Atlantic Oscillation is the dominant mode, but it plays a secondary role in the MOC fluctuations. During summer, the MOC variability is shown to have a significant impact on the atmosphere in the North Atlantic-European sector. The MOC influence is due to an interhemispheric sea surface temperature (SST) anomaly with opposite signs in the two hemispheres but largest amplitude in the northern one. The SST pattern driven by the MOC mostly resembles the model Atlantic Multidecadal Oscillation (AMO) and bears some similarity with the observed one. It is shown that the AMO reflects both the MOC influence and the local atmospheric forcing. Hence, the MOC influence on climate is best detected using lagged relations between climatic fields. The atmospheric response resembles the EAP, in a phase that might induce a weak positive feedback on the MOC. (orig.)

Biochemical leaf traits as indicators of tolerance potential in tree species from the Brazilian Atlantic Forest against oxidative environmental stressors.

Science.gov (United States)

Brandão, Solange E; Bulbovas, Patricia; Lima, Marcos E L; Domingos, Marisa

2017-01-01

The tolerance potential against the oxidative injury in native plants from forest ecosystems affected by environmental stressors depends on how efficiently they keep their pro-oxidant/antioxidant balance. Great variations in plant tolerance are expected, highlighting the higher relevance of measuring biochemical leaf trait indicators of oxidative injury in species with similar functions in the forest than in single species. The use of this functional approach seems very useful in the Brazilian Atlantic Forest because it still holds high plant diversity and was the focus of this study. We aimed at determining the tolerance potential of tree species from the Atlantic Forest remnants in SE Brazil against multiple oxidative environmental stressors. We assumed that pioneer tree species are more tolerant against oxidative stress than non-pioneer tree species and that their tolerance potential vary spatially in response to distinct combined effects of oxidative environmental stressors. The study was carried out in three Atlantic Forest remnants, which differ in physiognomy, species composition, climatic characteristics and air pollution exposure. Leaves of three pioneer and three non-pioneer species were collected from each forest remnant during wet (January 2015) and dry periods (June 2015), for analyses of non-enzymatic and enzymatic antioxidants and oxidative injury indicators. Both hypotheses were confirmed. The pioneer tree species displayed biochemical leaf traits (e.g. high levels of ascorbic acid, glutathione and carotenoids and lower lipid peroxidation) that indicate their higher potential tolerance against oxidative environmental stressors than non-pioneer species. The biochemical leaf traits of both successional groups of species varied between the forest remnants, in response to a linear combination of oxidative environmental stressors, from natural (relative humidity and temperature) and anthropogenic sources (ozone and nitrogen dioxide). Copyright © 2016

Bathymetric terrain model of the Atlantic margin for marine geological investigations

Science.gov (United States)

Andrews, Brian D.; Chaytor, Jason D.; ten Brink, Uri S.; Brothers, Daniel S.; Gardner, James V.; Lobecker, Elizabeth A.; Calder, Brian R.

2016-01-01

A bathymetric terrain model of the Atlantic margin covering almost 725,000 square kilometers of seafloor from the New England Seamounts in the north to the Blake Basin in the south is compiled from existing multibeam bathymetric data for marine geological investigations. Although other terrain models of the same area are extant, they are produced from either satellite-derived bathymetry at coarse resolution (ETOPO1), or use older bathymetric data collected by using a combination of single beam and multibeam sonars (Coastal Relief Model). The new multibeam data used to produce this terrain model have been edited by using hydrographic data processing software to maximize the quality, usability, and cartographic presentation of the combined 100-meter resolution grid. The final grid provides the largest high-resolution, seamless terrain model of the Atlantic margin..

Oil spill modeling input to the offshore environmental cost model (OECM) for US-BOEMRE's spill risk and costs evaluations

International Nuclear Information System (INIS)

French McCay, Deborah; Reich, Danielle; Rowe, Jill; Schroeder, Melanie; Graham, Eileen

2011-01-01

This paper simulates the consequences of oil spills using a planning model known as the Offshore Environmental Cost Model (OECM). This study aims at creating various predictive models for possible oil spill scenarios in marine waters. A crucial part of this investigation was the SIMAP model. It analyzes the distance and the direction covered by the spill under certain test conditions, generating a regression equation that simulates the impact of the spill. Tests were run in two different regions; the Mid-Atlantic region and the Chukchi Sea. Results showed that the higher wind speeds and higher water temperature of the Mid-Atlantic region had greater impact on wildlife and the water column respectively. However, short-line impact was higher in the Chukchi area due to the multi-directional wind. It was also shown that, because of their higher diffusivity in water, lighter crude oils had more impact than heavier oils. It was suggested that this model could ultimately be applied to other oil spill scenarios happening under similar conditions.

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.

Modelling size-fractionated primary production in the Atlantic Ocean from remote sensing

Science.gov (United States)

Brewin, Robert J. W.; Tilstone, Gavin H.; Jackson, Thomas; Cain, Terry; Miller, Peter I.; Lange, Priscila K.; Misra, Ankita; Airs, Ruth L.

2017-11-01

Marine primary production influences the transfer of carbon dioxide between the ocean and atmosphere, and the availability of energy for the pelagic food web. Both the rate and the fate of organic carbon from primary production are dependent on phytoplankton size. A key aim of the Atlantic Meridional Transect (AMT) programme has been to quantify biological carbon cycling in the Atlantic Ocean and measurements of total primary production have been routinely made on AMT cruises, as well as additional measurements of size-fractionated primary production on some cruises. Measurements of total primary production collected on the AMT have been used to evaluate remote-sensing techniques capable of producing basin-scale estimates of primary production. Though models exist to estimate size-fractionated primary production from satellite data, these have not been well validated in the Atlantic Ocean, and have been parameterised using measurements of phytoplankton pigments rather than direct measurements of phytoplankton size structure. Here, we re-tune a remote-sensing primary production model to estimate production in three size fractions of phytoplankton (10 μm) in the Atlantic Ocean, using measurements of size-fractionated chlorophyll and size-fractionated photosynthesis-irradiance experiments conducted on AMT 22 and 23 using sequential filtration-based methods. The performance of the remote-sensing technique was evaluated using: (i) independent estimates of size-fractionated primary production collected on a number of AMT cruises using 14C on-deck incubation experiments and (ii) Monte Carlo simulations. Considering uncertainty in the satellite inputs and model parameters, we estimate an average model error of between 0.27 and 0.63 for log10-transformed size-fractionated production, with lower errors for the small size class (10 μm), and errors generally higher in oligotrophic waters. Application to satellite data in 2007 suggests the contribution of cells 2 μm to total

Challenges of achieving Good Environmental Status in the Northeast Atlantic

Directory of Open Access Journals (Sweden)

Karen A. Alexander

2015-03-01

Full Text Available The sustainable exploitation of marine ecosystem services is dependent on achieving and maintaining an adequate ecosystem state to prevent undue deterioration. Within the European Union, the Marine Strategy Framework Directive (MSFD requires member states to achieve Good Environmental Status (GEnS, specified in terms of 11 descriptors. We analyzed the complexity of social-ecological factors to identify common critical issues that are likely to influence the achievement of GEnS in the Northeast Atlantic (NEA more broadly, using three case studies. A conceptual model developed using a soft systems approach highlights the complexity of social and ecological phenomena that influence, and are likely to continue to influence, the state of ecosystems in the NEA. The development of the conceptual model raised four issues that complicate the implementation of the MSFD, the majority of which arose in the Pressures and State sections of the model: variability in the system, cumulative effects, ecosystem resilience, and conflicting policy targets. The achievement of GEnS targets for the marine environment requires the recognition and negotiation of trade-offs across a broad policy landscape involving a wide variety of stakeholders in the public and private sectors. Furthermore, potential cumulative effects may introduce uncertainty, particularly in selecting appropriate management measures. There also are endogenous pressures that society cannot control. This uncertainty is even more obvious when variability within the system, e.g., climate change, is accounted for. Also, questions related to the resilience of the affected ecosystem to specific pressures must be raised, despite a lack of current knowledge. Achieving good management and reaching GEnS require multidisciplinary assessments. The soft systems approach provides one mechanism for bringing multidisciplinary information together to look at the problems in a different light.

Biodiversity patterns, environmental drivers and indicator species on a high-temperature hydrothermal edifice, Mid-Atlantic Ridge

OpenAIRE

Sarrazin, Jozée; Legendre, Pierre; de Busserolles, Fanny; Fabri, Marie-Claire; Guilini, Katja; Ivanenko, Viatcheslav N.; Morineaux, Marie; Vanreusel, Ann; Sarradin, Pierre-Marie

2015-01-01

Knowledge on quantitative faunal distribution patterns of hydrothermal communities in slow-spreading vent fields is particularly scarce, despite the importance of these ridges in the global mid-ocean system. This study assessed the composition, abundance and diversity of 12 benthic faunal assemblages from various locations on the Eiffel Tower edifice (Lucky Strike vent field, Mid-Atlantic Ridge) and investigated the role of key environmental conditions (temperature, total dissolved iron (TdFe...

78 FR 23224 - Fisheries of the South Atlantic; South Atlantic Fishery Management Council; Public Meeting

Science.gov (United States)

2013-04-18

... Agenda, Tuesday, May 7, 2013, 8:30 a.m. until 4:30 p.m. 1. Review draft Essential Fish Habitat (EFH... of the South Atlantic Fishery Management Council's Habitat & Environmental Protection Advisory Panel (AP); Coral AP; Joint Meeting of the Habitat & Environmental Protection AP and Coral AP; and Deepwater...

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

Use of variability modes to evaluate AR4 climate models over the Euro-Atlantic region

Energy Technology Data Exchange (ETDEWEB)

Casado, M.J.; Pastor, M.A. [Agencia Estatal de Meteorologia (AEMET), Madrid (Spain)

2012-01-15

This paper analyzes the ability of the multi-model simulations from the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) to simulate the main leading modes of variability over the Euro-Atlantic region in winter: the North-Atlantic Oscillation (NAO), the Scandinavian mode (SCAND), the East/Atlantic Oscillation (EA) and the East Atlantic/Western Russia mode (EA/WR). These modes of variability have been evaluated both spatially, by analyzing the intensity and location of their anomaly centres, as well as temporally, by focusing on the probability density functions and e-folding time scales. The choice of variability modes as a tool for climate model assessment can be justified by the fact that modes of variability determine local climatic conditions and their likely change may have important implications for future climate changes. It is found that all the models considered are able to simulate reasonably well these four variability modes, the SCAND being the mode which is best spatially simulated. From a temporal point of view the NAO and SCAND modes are the best simulated. UKMO-HadGEM1 and CGCM3.1(T63) are the models best at reproducing spatial characteristics, whereas CCSM3 and CGCM3.1(T63) are the best ones with regard to the temporal features. GISS-AOM is the model showing the worst performance, in terms of both spatial and temporal features. These results may bring new insight into the selection and use of specific models to simulate Euro-Atlantic climate, with some models being clearly more successful in simulating patterns of temporal and spatial variability than others. (orig.)

Influence of Tropical South Atlantic Sea Surface Temperatures on the Indian Summer monsoon in CMIP5 models

Science.gov (United States)

Kucharski, Fred; Joshi, Manish K.

2017-04-01

In this study the teleconnection from the tropical south Atlantic to the Indian monsoon has been assessed in observations and in 32 models from the World Climate Research Program (WCRP) Coupled Model Intercomparison Project Phase 5 (CMIP5). All models show that the regression pattern of tropics-wide Atlantic sea surface temperature (SST) anomalies onto the tropical south Atlantic index correlates well with that in observations, even though with varying spatial standard deviations. However, only about half of the 32 models considered show the correct sign of rainfall response over India to a warm anomaly in the south tropical Atlantic, which is a reduction of rainfall. On the other hand, models generally do show large-scale responses broadly consistent with the observations, and the signal over India depends on relatively subtle changes in the response. This response to a tropical south Atlantic warm (cold) anomaly is a low-level quadrupole in streamfunction with an anticyclonic (cyclonic) anomaly over the Arabian Sea and India. This anticyclonic (cyclonic) anomaly leads to a weakening (strengthening) of the Somali jet and low-level divergence (convergence) over India, both inducing a reduction (increase) of Indian rainfall. The models which do not show the correct rainfall response over India also show a response similar to the one indicated above, but with maximum of the anticyclonic (cyclonic) response shifted to the western Pacific. The large-scale Walker circulation adjustment to the tropical south Atlantic SST anomalies is identified as one of the factors which account for the differences in the low-level streamfunction response. Models (and the observations) with the correct sign of the rainfall signal over India show the dominant upper-level convergence (divergence) as response to a warm (cold) tropical south Atlantic in the western Pacific region, whereas models with the wrong sign of the rainfall signal show it predominantly in the central-eastern Pacific

About the Atlantic Ecology Division (AED) of EPA's National Health and Environmental Effects Research Laboratory

Science.gov (United States)

The Atlantic Ecology Division (AED), conducts innovative research and predictive modeling to assess and forecast the risks of anthropogenic stressors to near coastal waters and their watersheds, to develop tools to support resilient watersheds.

Developing New Modelling Tools for Environmental Flow Assessment in Regulated Salmon Rivers

Science.gov (United States)

Geris, Josie; Soulsby, Chris; Tetzlaff, Doerthe

2013-04-01

of the natural flow variability and the hydrological impacts of the regulation is unavailable, partly because pre-regulation data of existing hydropower schemes are lacking. Here we develop a novel modelling approach for characterising natural flow regimes and defining hydrological flow indices. This allows us to quantitatively assess the impacts of hydropower to better inform environmental flow requirements for the Atlantic salmon river ecosystem. Results are presented for the River Lyon (390 km2), a regulated headwater catchment of the River Tay. The HBV hydrological rainfall-runoff model is used to simulate flows, based on calibrated parameters from regulated flow data, with the current hydropower scheme active. For this, the HBV model is adapted to be able to incorporate water transfers and regulated flows. The natural hydrological indices are derived from the simulated pre-regulation data, and compared with those of the regulated data to investigate the impact of the regulation on these at different critical times for Atlantic salmon. The sensitivity of the system to change is also investigated to explore the extent to which flow variables can be modified without major degradation to the river's ecosystem, while still maintaining viable hydropower generation. The modelling approach presented will provide the basis for assessing impacts on hydrological flow indices and informing environmental flows in regions with similar heavily regulated mountain river ecosystems.

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

Influence of Atlantic SST anomalies on the atmospheric circulation in the Atlantic-European sector

Directory of Open Access Journals (Sweden)

E. Kestenare

2003-06-01

Full Text Available Recent studies of observational data suggest that Sea Surface Temperature (SST anomalies in the Atlantic Ocean have a significant influence on the atmospheric circulation in the Atlantic-European sector in early winter and in spring. After reviewing this work and showing that the spring signal is part of a global air-sea interaction, we analyze for comparison an ensemble of simulations with the ECHAM4 atmospheric general circulation model in T42 resolution forced by the observed distribution of SST and sea ice, and a simulation with the ECHAM4/OPA8 coupled model in T30 resolution. In the two cases, a significant influence of the Atlantic on the atmosphere is detected in the Atlantic-European sector. In the forced mode, ECHAM4 responds to SST anomalies from early spring to late summer, and also in early winter. The forcing involves SST anomalies not only in the tropical Atlantic, but also in the whole tropical band, suggesting a strong ENSO influence. The modeled signal resembles that seen in the observations in spring, but not in early winter. In the coupled mode, the Atlantic SST only has a significant influence on the atmosphere in summer. Although the SST anomaly is confined to the Atlantic, the summer signal shows some similarity with that seen in the forced simulations. However, there is no counterpart in the observations.

Virginia Atlantic Coast Recreational Use

Data.gov (United States)

Virginia Department of Environmental Quality — As a member of the Mid-Atlantic Regional Council on the Ocean (MARCO), Virginia, through its Coastal Zone Management (CZM) Program, collected information on how the...

VA Atlantic Coast Recreational Use

Data.gov (United States)

Virginia Department of Environmental Quality — As a member of the Mid-Atlantic Regional Council on the Ocean (MARCO), Virginia, through its Coastal Zone Management (CZM) Program, collected information on how the...

Distribution and Conservation of Davilla (Dilleniaceae in Brazilian Atlantic Forest Using Ecological Niche Modeling

Directory of Open Access Journals (Sweden)

Ismael Martins Pereira

2014-01-01

Full Text Available We have modeled the ecological niche for 12 plant species belonging to the genus Davilla (Dilleniaceae which occur in the Atlantic Forest of Brazil. This group includes endemic species lianas threatened by extinction and is therefore a useful indicator for forest areas requiring conservation. The aims are to compare the distribution and richness of species within the protected areas, assessing the degree of protection and gap analysis of reserves for this group. We used the Maxent algorithm with environmental and occurrence data, and produced geographic distribution maps. The results show that high species richness occurs in forest and coastal forest of Espírito Santo to Bahia states. The endemic species comprise D. flexuosa, D. macrocarpa, D. flexuosa, D. grandifolia, and D. sessilifolia. In the Atlantic Forest of southeastern Brazil, the following endemic species occur: D. tintinnabulata and D. glaziovii, with this latter species being included in the “red list” due habitat loss and predatory extractivism. The indicators of species richness in the coastal region of Bahia correspond with floristic inventories that point to this area having a high biodiversity. Although this region has several protected areas, there are gaps in reserves, which, combined with anthropogenic threats and fragmentation, have caused several problems for biodiversity.

Crude fucoidan content in two North Atlantic kelp species, Saccharina latissima and Laminaria digitata - seasonal variation and impact of environmental factors

DEFF Research Database (Denmark)

Bruhn, Annette; Janicek, Tina; Manns, Dirk Martin

2017-01-01

, the biochemical composition of brown algae displays a seasonal fluctuation driven by environmental factors and endogenous rhythms. To cultivate and harvest kelps with high yields of fucoidans, knowledge is needed on seasonal variation and impact of environmental conditions on the fucoidan content of brown algae....... The relations between the fucoidan content and key environmental factors (irradiance, nutrient availability, salinity and exposure) were examined by sampling natural populations of the common North Atlantic kelps, Saccharina latissima and Laminaria digitata, over a full year at Hanstholm in the North Sea...

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.

Arctic warming will promote Atlantic-Pacific fish interchange

DEFF Research Database (Denmark)

Wisz, Mary; Broennimann, O.; Grønkjær, Peter

2015-01-01

the interchange of marine biota between the two seas. Here, we forecast the potential northward progression of 515 fish species following climate change, and report the rate of potential species interchange between the Atlantic and the Pacific via the Northwest Passage and the Northeast Passage. For this, we...... projected niche-based models under climate change scenarios and simulated the spread of species through the passages when climatic conditions became suitable. Results reveal a complex range of responses during this century, and accelerated interchange after 2050. By 2100 up to 41 species could enter......Throughout much of the Quaternary Period, inhospitable environmental conditions above the Arctic Circle have been a formidable barrier separating most marine organisms in the North Atlantic from those in the North Pacific. Rapid warming has begun to lift this barrier, potentially facilitating...

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

Contrasting spatial structures of Atlantic Multidecadal Oscillation between observations and slab ocean model simulations

Science.gov (United States)

Sun, Cheng; Li, Jianping; Kucharski, Fred; Xue, Jiaqing; Li, Xiang

2018-04-01

The spatial structure of Atlantic multidecadal oscillation (AMO) is analyzed and compared between the observations and simulations from slab ocean models (SOMs) and fully coupled models. The observed sea surface temperature (SST) pattern of AMO is characterized by a basin-wide monopole structure, and there is a significantly high degree of spatial coherence of decadal SST variations across the entire North Atlantic basin. The observed SST anomalies share a common decadal-scale signal, corresponding to the basin-wide average (i. e., the AMO). In contrast, the simulated AMO in SOMs (AMOs) exhibits a tripole-like structure, with the mid-latitude North Atlantic SST showing an inverse relationship with other parts of the basin, and the SOMs fail to reproduce the observed strong spatial coherence of decadal SST variations associated with the AMO. The observed spatial coherence of AMO SST anomalies is identified as a key feature that can be used to distinguish the AMO mechanism. The tripole-like SST pattern of AMOs in SOMs can be largely explained by the atmosphere-forced thermodynamics mechanism due to the surface heat flux changes associated with the North Atlantic Oscillation (NAO). The thermodynamic forcing of AMOs by the NAO gives rise to a simultaneous inverse NAO-AMOs relationship at both interannual and decadal timescales and a seasonal phase locking of the AMOs variability to the cold season. However, the NAO-forced thermodynamics mechanism cannot explain the observed NAO-AMO relationship and the seasonal phase locking of observed AMO variability to the warm season. At decadal timescales, a strong lagged relationship between NAO and AMO is observed, with the NAO leading by up to two decades, while the simultaneous correlation of NAO with AMO is weak. This lagged relationship and the spatial coherence of AMO can be well understood from the view point of ocean dynamics. A time-integrated NAO index, which reflects the variations in Atlantic meridional overturning

The modern and glacial overturning circulation in the Atlantic ocean in PMIP coupled model simulations

Directory of Open Access Journals (Sweden)

S. L. Weber

2007-01-01

Full Text Available This study analyses the response of the Atlantic meridional overturning circulation (AMOC to LGM forcings and boundary conditions in nine PMIP coupled model simulations, including both GCMs and Earth system Models of Intermediate Complexity. Model results differ widely. The AMOC slows down considerably (by 20–40% during the LGM as compared to the modern climate in four models, there is a slight reduction in one model and four models show a substantial increase in AMOC strength (by 10–40%. It is found that a major controlling factor for the AMOC response is the density contrast between Antarctic Bottom Water (AABW and North Atlantic Deep Water (NADW at their source regions. Changes in the density contrast are determined by the opposing effects of changes in temperature and salinity, with more saline AABW as compared to NADW consistently found in all models and less cooling of AABW in all models but one. In only two models is the AMOC response during the LGM directly related to the response in net evaporation over the Atlantic basin. Most models show large changes in the ocean freshwater transports into the basin, but this does not seem to affect the AMOC response. Finally, there is some dependence on the accuracy of the control state.

Revised draft environmental statement related to construction of Atlantic Generating Station Units 1 and 2 (Docket Nos. STN 50-477 and STN 50-478)

International Nuclear Information System (INIS)

1976-10-01

The proposed action is the issuance of a construction permit to Public Service Electric and Gas Company (PDE and G) for the construction of the Atlantic Generating Station (AGS), Units 1 and 2. The AGS is the first nuclear power station in the United States proposed for construction in the offshore waters on the continental shelf. The AHS will be located in the Atlantic Ocean 2.8 miles offshore of Atlantic and Ocean countries. New Jersey, 11 miles northeast of Atlantic City, and will consist of two floating nuclear power plants enclosed in a protective rubble-mound breakwater. Both plants will be identical, of standardized design, and will employ pressurized water reactors to produce up to approximately 3425 megawatts thermal (MWt) each. Steam turbine generators will use this heat to produce up to approximately 1150 megawatts of electrical power (MWe) per unit. The main condensers will be cooled by the flow of seawater drawn from within the breakwater and discharged shoreward and external to the breakwater. This statement identifies various environmental aspects and potential adverse effects associated with the construction and operation of the AGS. Based upon an approximate two-year review period which included a multidisciplined assessment of extensive survey and modeling data, these effects are considered by the staff to be of a generally acceptable nature. Breakwater construction will result in the destruction of 100 acres of benthic infauna (burrowing animals) and the development of a reef-type community on the breakwater. The production of new biomass (standing crop) by the reef community is expected to compensate for the infaunal biomass destroyed by dredging and will contribute mainly to the local sport fishery. 93 figs., 110 tabs

Hierarchical modeling of bycatch rates of sea turtles in the western North Atlantic

Science.gov (United States)

Gardner, B.; Sullivan, P.J.; Epperly, S.; Morreale, S.J.

2008-01-01

Previous studies indicate that the locations of the endangered loggerhead Caretta caretta and critically endangered leatherback Dermochelys coriacea sea turtles are influenced by water temperatures, and that incidental catch rates in the pelagic longline fishery vary by region. We present a Bayesian hierarchical model to examine the effects of environmental variables, including water temperature, on the number of sea turtles captured in the US pelagic longline fishery in the western North Atlantic. The modeling structure is highly flexible, utilizes a Bayesian model selection technique, and is fully implemented in the software program WinBUGS. The number of sea turtles captured is modeled as a zero-inflated Poisson distribution and the model incorporates fixed effects to examine region-specific differences in the parameter estimates. Results indicate that water temperature, region, bottom depth, and target species are all significant predictors of the number of loggerhead sea turtles captured. For leatherback sea turtles, the model with only target species had the most posterior model weight, though a re-parameterization of the model indicates that temperature influences the zero-inflation parameter. The relationship between the number of sea turtles captured and the variables of interest all varied by region. This suggests that management decisions aimed at reducing sea turtle bycatch may be more effective if they are spatially explicit. ?? Inter-Research 2008.

Environmental drivers of vertical distribution in diapausing Calanus copepods in the Northwest Atlantic

Science.gov (United States)

Krumhansl, Kira A.; Head, Erica J. H.; Pepin, Pierre; Plourde, Stéphane; Record, Nicholas R.; Runge, Jeffrey A.; Johnson, Catherine L.

2018-03-01

Copepods of the genus Calanus play a critical trophic role in the North Atlantic ecosystems, where they serve as an important source of energy-rich food for fish and marine mammals, including the endangered North Atlantic right whale. As a strategy for coping with unfavorable near-surface conditions, Calanus enter diapause and migrate to deep water in late summer and fall after feeding and accumulating lipid stores in spring and summer. In order to assess the most important physical drivers of vertical distribution of diapausing Calanus, we synthesized existing depth-stratified abundance data of Calanus finmarchicus and Calanus hyperboreus from the Northwest Atlantic continental shelf and slope regions, spanning Newfoundland in the northeast to the Gulf of Maine in the southwest. Bottom depth strongly constrained the depth and shape of vertical distributions, with distributions becoming deeper and less compact as bottom depth increased. Diapausing Calanus, observed across a broad range of temperature (T) and in-situ density (σ) conditions (T = -1.0 to 14.4 °C, σ = 25.3-28.1 kg m-3), tended to distribute at depths with the coldest temperatures locally available. Over the shelf, diapausing Calanus in the GOM and SS generally did not have access to temperatures considered optimal for diapause (<5 °C), in many cases occurring at temperatures well above this threshold. Diapausing Calanus in both habitats were most commonly below the Cold Intermediate Layer (CIL), a feature formed through wind-driven mixing during the winter, but this effect was more obvious over the shelf than in slope waters. Our analysis highlights key differences in the vertical distributions of diapausing Calanus over the shelf vs. the slope, having regional implications for ecological dynamics and population persistence in the face of warming temperatures. In general, understanding factors that influence vertical distributions of diapausing Calanus will allow us to more accurately predict how

Regional analysis of soil-atmosphere nitrous oxide emissions in the Northern Atlantic Zone of Costa Rica

NARCIS (Netherlands)

Plant, R.A.J.

2000-01-01

Regional analysis of greenhouse gas emissions is becoming increasingly important in answering questions related to environmental change, and typically employs a Geographic Information System (GIS) linked with a process-based simulation model. For the Northern Atlantic Zone (NAZ) in Costa Rica (281

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

Identifying the European fossil fuel plumes in the atmosphere over the Northeast Atlantic Region through isotopic observations and numerical modelling

DEFF Research Database (Denmark)

Geels, C.; Christensen, J.H.; Hansen, A.W.

2006-01-01

Atmospheric transport, C-14. fossil fuel CO_2, numerical modeling, the north East Atlantic Region Udgivelsesdato: 18 August......Atmospheric transport, C-14. fossil fuel CO_2, numerical modeling, the north East Atlantic Region Udgivelsesdato: 18 August...

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.

Model under-representation of decadal Pacific trade wind trends and its link to tropical Atlantic bias

Science.gov (United States)

Kajtar, Jules B.; Santoso, Agus; McGregor, Shayne; England, Matthew H.; Baillie, Zak

2018-02-01

The strengthening of the Pacific trade winds in recent decades has been unmatched in the observational record stretching back to the early twentieth century. This wind strengthening has been connected with numerous climate-related phenomena, including accelerated sea-level rise in the western Pacific, alterations to Indo-Pacific ocean currents, increased ocean heat uptake, and a slow-down in the rate of global-mean surface warming. Here we show that models in the Coupled Model Intercomparison Project phase 5 underestimate the observed range of decadal trends in the Pacific trade winds, despite capturing the range in decadal sea surface temperature (SST) variability. Analysis of observational data suggests that tropical Atlantic SST contributes considerably to the Pacific trade wind trends, whereas the Atlantic feedback in coupled models is muted. Atmosphere-only simulations forced by observed SST are capable of recovering the time-variation and the magnitude of the trade wind trends. Hence, we explore whether it is the biases in the mean or in the anomalous SST patterns that are responsible for the under-representation in fully coupled models. Over interannual time-scales, we find that model biases in the patterns of Atlantic SST anomalies are the strongest source of error in the precipitation and atmospheric circulation response. In contrast, on decadal time-scales, the magnitude of the model biases in Atlantic mean SST are directly linked with the trade wind variability response.

Crude fucoidan content in two North Atlantic kelp species, Saccharina latissima and Laminaria digitata - seasonal variation and impact of environmental factors

DEFF Research Database (Denmark)

Bruhn, Annette; Janicek, Tina; Manns, Dirk Martin

2017-01-01

, the biochemical composition of brown algae displays a seasonal fluctuation driven by environmental factors and endogenous rhythms. To cultivate and harvest kelps with high yields of fucoidans, knowledge is needed on seasonal variation and impact of environmental conditions on the fucoidan content of brown algae....... The relations between the fucoidan content and key environmental factors (irradiance, nutrient availability, salinity and exposure) were examined by sampling natural populations of the common North Atlantic kelps, Saccharina latissima and Laminaria digitata, over a full year at Hanstholm in the North Sea...... an increased content of fucoidan in a cultivation scenario and emphasizes the need for knowledge on performance of local kelp ecotypes....

Large-Scale Prediction of Seagrass Distribution Integrating Landscape Metrics and Environmental Factors: The Case of Cymodocea nodosa (Mediterranean–Atlantic)

KAUST Repository

Chefaoui, Rosa M.

2015-05-05

Understanding the factors that affect seagrass meadows encompassing their entire range of distribution is challenging yet important for their conservation. Here, we predict the realized and potential distribution for the species Cymodocea nodosa modelling its environmental niche in the Mediterranean and adjacent Atlantic coastlines. We use a combination of environmental variables and landscape metrics to perform a suite of predictive algorithms which enables examination of the niche and find suitable habitats for the species. The most relevant environmental variables defining the distribution of C. nodosa were sea surface temperature (SST) and salinity. We found suitable habitats at SST from 5.8 °C to 26.4 °C and salinity ranging from 17.5 to 39.3. Optimal values of mean winter wave height ranged between 1.2 and 1.5 m, while waves higher than 2.5 m seemed to limit the presence of the species. The influence of nutrients and pH, despite having weight on the models, was not so clear in terms of ranges that confine the distribution of the species. Landscape metrics able to capture variation in the coastline enhanced significantly the accuracy of the models, despite the limitations caused by the scale of the study. We found potential suitable areas not occupied by the seagrass mainly in coastal regions of North Africa and the Adriatic coast of Italy. The present study describes the realized and potential distribution of a seagrass species, providing the first global model of the factors that can be shaping the environmental niche of C. nodosa throughout its range. We identified the variables constraining its distribution as well as thresholds delineating its environmental niche. Landscape metrics showed promising prospects for the prediction of coastal species dependent on the shape of the coast. By contrasting predictive approaches, we defined the variables affecting the distributional areas that seem unsuitable for C. nodosa as well as those suitable habitats not

Large-Scale Prediction of Seagrass Distribution Integrating Landscape Metrics and Environmental Factors: The Case of Cymodocea nodosa (Mediterranean–Atlantic)

KAUST Repository

Chefaoui, Rosa M.; Assis, Jorge; Duarte, Carlos M.; Serrã o, Ester A.

2015-01-01

Understanding the factors that affect seagrass meadows encompassing their entire range of distribution is challenging yet important for their conservation. Here, we predict the realized and potential distribution for the species Cymodocea nodosa modelling its environmental niche in the Mediterranean and adjacent Atlantic coastlines. We use a combination of environmental variables and landscape metrics to perform a suite of predictive algorithms which enables examination of the niche and find suitable habitats for the species. The most relevant environmental variables defining the distribution of C. nodosa were sea surface temperature (SST) and salinity. We found suitable habitats at SST from 5.8 °C to 26.4 °C and salinity ranging from 17.5 to 39.3. Optimal values of mean winter wave height ranged between 1.2 and 1.5 m, while waves higher than 2.5 m seemed to limit the presence of the species. The influence of nutrients and pH, despite having weight on the models, was not so clear in terms of ranges that confine the distribution of the species. Landscape metrics able to capture variation in the coastline enhanced significantly the accuracy of the models, despite the limitations caused by the scale of the study. We found potential suitable areas not occupied by the seagrass mainly in coastal regions of North Africa and the Adriatic coast of Italy. The present study describes the realized and potential distribution of a seagrass species, providing the first global model of the factors that can be shaping the environmental niche of C. nodosa throughout its range. We identified the variables constraining its distribution as well as thresholds delineating its environmental niche. Landscape metrics showed promising prospects for the prediction of coastal species dependent on the shape of the coast. By contrasting predictive approaches, we defined the variables affecting the distributional areas that seem unsuitable for C. nodosa as well as those suitable habitats not

Variability along the Atlantic water pathway in the forced Norwegian Earth System Model

Science.gov (United States)

Langehaug, H. R.; Sandø, A. B.; Årthun, M.; Ilıcak, M.

2018-03-01

The growing attention on mechanisms that can provide predictability on interannual-to-decadal time scales, makes it necessary to identify how well climate models represent such mechanisms. In this study we use a high (0.25° horizontal grid) and a medium (1°) resolution version of a forced global ocean-sea ice model, utilising the Norwegian Earth System Model, to assess the impact of increased ocean resolution. Our target is the simulation of temperature and salinity anomalies along the pathway of warm Atlantic water in the subpolar North Atlantic and the Nordic Seas. Although the high resolution version has larger biases in general at the ocean surface, the poleward propagation of thermohaline anomalies is better resolved in this version, i.e., the time for an anomaly to travel northward is more similar to observation based estimates. The extent of these anomalies can be rather large in both model versions, as also seen in observations, e.g., stretching from Scotland to northern Norway. The easternmost branch into the Nordic and Barents Seas, carrying warm Atlantic water, is also improved by higher resolution, both in terms of mean heat transport and variability in thermohaline properties. A more detailed assessment of the link between the North Atlantic Ocean circulation and the thermohaline anomalies at the entrance of the Nordic Seas reveals that the high resolution is more consistent with mechanisms that are previously published. This suggests better dynamics and variability in the subpolar region and the Nordic Seas in the high resolution compared to the medium resolution. This is most likely due a better representation of the mean circulation in the studied region when using higher resolution. As the poleward propagation of ocean heat anomalies is considered to be a key source of climate predictability, we recommend that similar methodology presented herein should be performed on coupled climate models that are used for climate prediction.

Knowing the Brazilian Atlantic Rainforest in childhood: a contribution of the theory of multiple intelligence for environmental education

Directory of Open Access Journals (Sweden)

Valerie Nicollier

2009-12-01

Full Text Available This study is grounded in the cognitive sciences and represents a comprehensive inquiry into children's environmental knowledge. It started with an investigation of a specific situation: studying an urban population – stigmatized by a history of local environmental destruction, unconsciously wrought upon an area that is nowadays acknowledged as a natural biodiversity hotspot, the Brazilian Atlantic Rainforest. Based on the Multiple Intelligence Theory (MIT, that describes the presence of several intelligences in human beings, including a naturalist intelligence, this study aimed at improving the understanding of abilities related to environmental knowledge and the differentiation of such abilities from other ways of knowing usually valued in mainstream education. Forty-five (45 students of a primary school located in south Bahia, Brazil, their teachers, and their parents participated in this investigation between 2002 to 2004. Results suggest that the cognitive domains which are subjacent to environmental knowledge are place specific and need to be stimulated in primary schools by formulating more attractive, efficient, and innovative environmental educational methodologies.

Bioenergetics modeling of the annual consumption of zooplankton by pelagic fish feeding in the Northeast Atlantic

DEFF Research Database (Denmark)

Bachiller, Eneko; Utne, Kjell Rong; Jansen, Teunis

2018-01-01

The present study uses bioenergetics modeling to estimate the annual consumption of the main zooplankton groups by some of the most commercially important planktivorous fish stocks in the Northeast Atlantic, namely Norwegian spring-spawning (NSS) herring (Clupea harengus), blue whiting (Micromesi......The present study uses bioenergetics modeling to estimate the annual consumption of the main zooplankton groups by some of the most commercially important planktivorous fish stocks in the Northeast Atlantic, namely Norwegian spring-spawning (NSS) herring (Clupea harengus), blue whiting...

77 FR 65380 - 2012 Fall Joint Meeting of the Ozone Transport Commission and the Mid-Atlantic Northeast...

Science.gov (United States)

2012-10-26

... ENVIRONMENTAL PROTECTION AGENCY [FRL-9745-9] 2012 Fall Joint Meeting of the Ozone Transport Commission and the Mid-Atlantic Northeast Visibility Union AGENCY: Environmental Protection Agency (EPA... Fall Meeting of the Ozone Transport Commission (OTC) and the Mid-Atlantic Northeast Visibility Union...

Velocity Model for CO2 Sequestration in the Southeastern United States Atlantic Continental Margin

Science.gov (United States)

Ollmann, J.; Knapp, C. C.; Almutairi, K.; Almayahi, D.; Knapp, J. H.

2017-12-01

The sequestration of carbon dioxide (CO2) is emerging as a major player in offsetting anthropogenic greenhouse gas emissions. With 40% of the United States' anthropogenic CO2 emissions originating in the southeast, characterizing potential CO2 sequestration sites is vital to reducing the United States' emissions. The goal of this research project, funded by the Department of Energy (DOE), is to estimate the CO2 storage potential for the Southeastern United States Atlantic Continental Margin. Previous studies find storage potential in the Atlantic continental margin. Up to 16 Gt and 175 Gt of storage potential are estimated for the Upper Cretaceous and Lower Cretaceous formations, respectively. Considering 2.12 Mt of CO2 are emitted per year by the United States, substantial storage potential is present in the Southeastern United States Atlantic Continental Margin. In order to produce a time-depth relationship, a velocity model must be constructed. This velocity model is created using previously collected seismic reflection, refraction, and well data in the study area. Seismic reflection horizons were extrapolated using well log data from the COST GE-1 well. An interpolated seismic section was created using these seismic horizons. A velocity model will be made using P-wave velocities from seismic reflection data. Once the time-depth conversion is complete, the depths of stratigraphic units in the seismic refraction data will be compared to the newly assigned depths of the seismic horizons. With a lack of well control in the study area, the addition of stratigraphic unit depths from 171 seismic refraction recording stations provides adequate data to tie to the depths of picked seismic horizons. Using this velocity model, the seismic reflection data can be presented in depth in order to estimate the thickness and storage potential of CO2 reservoirs in the Southeastern United States Atlantic Continental Margin.

75 FR 10450 - Fisheries of the Northeastern United States; Atlantic Bluefish Fisheries; 2010 Atlantic Bluefish...

Science.gov (United States)

2010-03-08

... recreational landings for the 2010 fishing year by using simple linear regression of the recent (2001-2008... specifications document, including the Environmental Assessment and Initial Regulatory Flexibility Analysis (EA...-Atlantic RSA Program was published on January 2, 2009 (74 FR 72). For analysis of impacts for each TAL...

78 FR 62587 - Fisheries of the South Atlantic; South Atlantic Fishery Management Council; Public Meeting

Science.gov (United States)

2013-10-22

... Essential Fish Habitat Policy Statements and receive training on the use of the Regional Habitat and... meeting of the South Atlantic Fishery Management Council's Habitat and Environmental Protection (Habitat... of its Habitat AP in St. Petersburg, FL. The meeting is open to the public. DATES: The meeting will...

75 FR 65298 - Fisheries of the South Atlantic; South Atlantic Fishery Management Council; Public Meeting

Science.gov (United States)

2010-10-22

... five-year Essential Fish Habitat review, the Governor's South Atlantic Alliance Action Plan, a status... its Habitat and Environmental Protection (Habitat) Advisory Panel in North Charleston, SC. DATES: [email protected] . SUPPLEMENTARY INFORMATION: Members of the Habitat Advisory Panel will meet from 9 a.m.-5 p.m...

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.

Genomic organization and evolution of the Atlantic salmon hemoglobin repertoire

Directory of Open Access Journals (Sweden)

Phillips Ruth B

2010-10-01

Full Text Available Abstract Background The genomes of salmonids are considered pseudo-tetraploid undergoing reversion to a stable diploid state. Given the genome duplication and extensive biological data available for salmonids, they are excellent model organisms for studying comparative genomics, evolutionary processes, fates of duplicated genes and the genetic and physiological processes associated with complex behavioral phenotypes. The evolution of the tetrapod hemoglobin genes is well studied; however, little is known about the genomic organization and evolution of teleost hemoglobin genes, particularly those of salmonids. The Atlantic salmon serves as a representative salmonid species for genomics studies. Given the well documented role of hemoglobin in adaptation to varied environmental conditions as well as its use as a model protein for evolutionary analyses, an understanding of the genomic structure and organization of the Atlantic salmon α and β hemoglobin genes is of great interest. Results We identified four bacterial artificial chromosomes (BACs comprising two hemoglobin gene clusters spanning the entire α and β hemoglobin gene repertoire of the Atlantic salmon genome. Their chromosomal locations were established using fluorescence in situ hybridization (FISH analysis and linkage mapping, demonstrating that the two clusters are located on separate chromosomes. The BACs were sequenced and assembled into scaffolds, which were annotated for putatively functional and pseudogenized hemoglobin-like genes. This revealed that the tail-to-tail organization and alternating pattern of the α and β hemoglobin genes are well conserved in both clusters, as well as that the Atlantic salmon genome houses substantially more hemoglobin genes, including non-Bohr β globin genes, than the genomes of other teleosts that have been sequenced. Conclusions We suggest that the most parsimonious evolutionary path leading to the present organization of the Atlantic salmon

Genomic organization and evolution of the Atlantic salmon hemoglobin repertoire

Science.gov (United States)

2010-01-01

Background The genomes of salmonids are considered pseudo-tetraploid undergoing reversion to a stable diploid state. Given the genome duplication and extensive biological data available for salmonids, they are excellent model organisms for studying comparative genomics, evolutionary processes, fates of duplicated genes and the genetic and physiological processes associated with complex behavioral phenotypes. The evolution of the tetrapod hemoglobin genes is well studied; however, little is known about the genomic organization and evolution of teleost hemoglobin genes, particularly those of salmonids. The Atlantic salmon serves as a representative salmonid species for genomics studies. Given the well documented role of hemoglobin in adaptation to varied environmental conditions as well as its use as a model protein for evolutionary analyses, an understanding of the genomic structure and organization of the Atlantic salmon α and β hemoglobin genes is of great interest. Results We identified four bacterial artificial chromosomes (BACs) comprising two hemoglobin gene clusters spanning the entire α and β hemoglobin gene repertoire of the Atlantic salmon genome. Their chromosomal locations were established using fluorescence in situ hybridization (FISH) analysis and linkage mapping, demonstrating that the two clusters are located on separate chromosomes. The BACs were sequenced and assembled into scaffolds, which were annotated for putatively functional and pseudogenized hemoglobin-like genes. This revealed that the tail-to-tail organization and alternating pattern of the α and β hemoglobin genes are well conserved in both clusters, as well as that the Atlantic salmon genome houses substantially more hemoglobin genes, including non-Bohr β globin genes, than the genomes of other teleosts that have been sequenced. Conclusions We suggest that the most parsimonious evolutionary path leading to the present organization of the Atlantic salmon hemoglobin genes involves

78 FR 54644 - 2013 Fall Joint Meeting of the Ozone Transport Commission and the Mid-Atlantic Northeast...

Science.gov (United States)

2013-09-05

... Transport Commission and the Mid-Atlantic Northeast Visibility Union AGENCY: Environmental Protection Agency...-Atlantic Northeast Visibility Union (MANE-VU). The meeting agenda will include topics regarding reducing...-level ozone formation, transport, and control within the OTR. The Mid-Atlantic/Northeast Visibility...

Factors regulating early life history dispersal of Atlantic cod (Gadus morhua) from coastal Newfoundland.

Science.gov (United States)

Stanley, Ryan R E; deYoung, Brad; Snelgrove, Paul V R; Gregory, Robert S

2013-01-01

To understand coastal dispersal dynamics of Atlantic cod (Gadus morhua), we examined spatiotemporal egg and larval abundance patterns in coastal Newfoundland. In recent decades, Smith Sound, Trinity Bay has supported the largest known overwintering spawning aggregation of Atlantic cod in the region. We estimated spawning and dispersal characteristics for the Smith Sound-Trinity Bay system by fitting ichthyoplankton abundance data to environmentally-driven, simplified box models. Results show protracted spawning, with sharply increased egg production in early July, and limited dispersal from the Sound. The model for the entire spawning season indicates egg export from Smith Sound is 13%•day(-1) with a net mortality of 27%•day(-1). Eggs and larvae are consistently found in western Trinity Bay with little advection from the system. These patterns mirror particle tracking models that suggest residence times of 10-20 days, and circulation models indicating local gyres in Trinity Bay that act in concert with upwelling dynamics to retain eggs and larvae. Our results are among the first quantitative dispersal estimates from Smith Sound, linking this spawning stock to the adjacent coastal waters. These results illustrate the biophysical interplay regulating dispersal and connectivity originating from inshore spawning of coastal northwest Atlantic.

Factors regulating early life history dispersal of Atlantic cod (Gadus morhua from coastal Newfoundland.

Directory of Open Access Journals (Sweden)

Ryan R E Stanley

Full Text Available To understand coastal dispersal dynamics of Atlantic cod (Gadus morhua, we examined spatiotemporal egg and larval abundance patterns in coastal Newfoundland. In recent decades, Smith Sound, Trinity Bay has supported the largest known overwintering spawning aggregation of Atlantic cod in the region. We estimated spawning and dispersal characteristics for the Smith Sound-Trinity Bay system by fitting ichthyoplankton abundance data to environmentally-driven, simplified box models. Results show protracted spawning, with sharply increased egg production in early July, and limited dispersal from the Sound. The model for the entire spawning season indicates egg export from Smith Sound is 13%•day(-1 with a net mortality of 27%•day(-1. Eggs and larvae are consistently found in western Trinity Bay with little advection from the system. These patterns mirror particle tracking models that suggest residence times of 10-20 days, and circulation models indicating local gyres in Trinity Bay that act in concert with upwelling dynamics to retain eggs and larvae. Our results are among the first quantitative dispersal estimates from Smith Sound, linking this spawning stock to the adjacent coastal waters. These results illustrate the biophysical interplay regulating dispersal and connectivity originating from inshore spawning of coastal northwest Atlantic.

Extended imposex monitoring in N Atlantic Spain confirms punctual attainment of European environmental objectives for TBT.

Science.gov (United States)

Ruiz, José M; Carro, Belén; Albaina, Naiara; Barreiro, Rodolfo; Rial, Diego; Bellas, Juan

2018-01-01

Legislation in the European Union (EU) aimed at reaching by 2015 a Good Ecological Status in regard to tributyltin (TBT, the biocide used in traditional antifouling paints). With a view to check such an achievement in N Atlantic Spain, baseline monitoring of gastropod imposex (the recommended assessment tool) was extended up to that date. In Galicia (the Western part of the study area) the use of the rock snail Nucella lapillus since 1996 had shown this environmental objective to be met as soon as 2009, but new surveys reveal no further improvement thereafter. As for the Eastern Cantabrian coast, imposex levels in the mud snail Nassarius reticulatus progressively declined from 2006 to 2015, when records finally complied with expectations. Both data sets are confronted and discussed in relation to the diverse environmental factors that may be determining the distribution of gastropods in these regions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Immune and individual level effects of environmental pollutants in North-Atlantic top predators

DEFF Research Database (Denmark)

Desforges, Jean-Pierre

2017-01-01

techniques can be used to assess effects on specific health endpoints. To date, however, most studies focus on single compound exposures, rather than realistic complex mixtures, and little has been done to extrapolate molecular effects to higher levels of biological organization. The aim of my PhD was to use...... a unique combination of approaches, namely statistical meta-analyses, in vitro experimentation, analytical chemistry, and ecological modeling, to gain further insight into pollutant accumulation and effects at molecular and organism levels in North-Atlantic top predators....

Modeling environmental policy

International Nuclear Information System (INIS)

Martin, W.E.; McDonald, L.A.

1997-01-01

The eight book chapters demonstrate the link between the physical models of the environment and the policy analysis in support of policy making. Each chapter addresses an environmental policy issue using a quantitative modeling approach. The volume addresses three general areas of environmental policy - non-point source pollution in the agricultural sector, pollution generated in the extractive industries, and transboundary pollutants from burning fossil fuels. The book concludes by discussing the modeling efforts and the use of mathematical models in general. Chapters are entitled: modeling environmental policy: an introduction; modeling nonpoint source pollution in an integrated system (agri-ecological); modeling environmental and trade policy linkages: the case of EU and US agriculture; modeling ecosystem constraints in the Clean Water Act: a case study in Clearwater National Forest (subject to discharge from metal mining waste); costs and benefits of coke oven emission controls; modeling equilibria and risk under global environmental constraints (discussing energy and environmental interrelations); relative contribution of the enhanced greenhouse effect on the coastal changes in Louisiana; and the use of mathematical models in policy evaluations: comments. The paper on coke area emission controls has been abstracted separately for the IEA Coal Research CD-ROM

North Atlantic 20th century multidecadal variability in coupled climate models: sea surface temperature and ocean overturning circulation

Directory of Open Access Journals (Sweden)

I. Medhaug

2011-06-01

Full Text Available Output from a total of 24 state-of-the-art Atmosphere-Ocean General Circulation Models is analyzed. The models were integrated with observed forcing for the period 1850–2000 as part of the Intergovernmental Panel on Climate Change (IPCC Fourth Assessment Report. All models show enhanced variability at multi-decadal time scales in the North Atlantic sector similar to the observations, but with a large intermodel spread in amplitudes and frequencies for both the Atlantic Multidecadal Oscillation (AMO and the Atlantic Meridional Overturning Circulation (AMOC. The models, in general, are able to reproduce the observed geographical patterns of warm and cold episodes, but not the phasing such as the early warming (1930s–1950s and the following colder period (1960s–1980s. This indicates that the observed 20th century extreme in temperatures are due to primarily a fortuitous phasing of intrinsic climate variability and not dominated by external forcing. Most models show a realistic structure in the overturning circulation, where more than half of the available models have a mean overturning transport within the observed estimated range of 13–24 Sverdrup. Associated with a stronger than normal AMOC, the surface temperature is increased and the sea ice extent slightly reduced in the North Atlantic. Individual models show potential for decadal prediction based on the relationship between the AMO and AMOC, but the models strongly disagree both in phasing and strength of the covariability. This makes it difficult to identify common mechanisms and to assess the applicability for predictions.

High Resolution Model Development to Quantify the Impact of Icebergs on the Stability of the Atlantic Meridional Overturning Circulation

Energy Technology Data Exchange (ETDEWEB)

Condron, Alan [Univ. of Massachusetts, Amherst, MA (United States)

2016-10-18

In the present-day North Atlantic Ocean, relatively warm and salty water moves northwards from the tropics to the high latitudes, sinks, and returns southward towards the equator as North Atlantic Deep Water, forming the so called Atlantic Meridional Overturning Circulation (AMOC). It has been found that the stability of the AMOC is non-linearly related to the freshwater budget of the North Atlantic. In this way, additional fresh water can be added to the ocean with little impact, until a tipping point is reached that causes the AMOC to suddenly weaken and the Northern Hemisphere to abruptly cool. A great deal of uncertainty still remains over the sensitivity of the AMOC to changes in freshwater discharge as a result of the unrealistic manner in which freshwater has historically been added to climate models. Frequently, freshwater is discharged in ocean models entirely as liquid water, but in reality a large fraction of freshwater entering the ocean is ice calving from marine glaciers (half for Antarctica and two-thirds for Greenland). To more accurately quantify AMOC sensitivity to past and future changes in freshwater input, this project developed a comprehensive iceberg model to more realistically simulate the interaction between the cryosphere and the oceans at high-latitudes. The iceberg model created is written in Fortran90 and designed to scale efficiently on High Performance Computing (HPC) clusters so that tens-of-thousands of icebergs can be simulated at any time. Experiments performed with our model showed that in the Pleistocene there would have been enormous floods of freshwater released into the North Atlantic that would have transported icebergs and meltwater along the entire east coast of the United States, as far south as Florida Keys. In addition, high-resolution, modern-day, model simulations showed that if the Greenland Ice Sheet continues to melt at its current rate then there will be a 6-fold increase in the number of icebergs drifting in the

Spatial variation of dung beetle assemblages associated with forest structure in remnants of southern Brazilian Atlantic Forest

Directory of Open Access Journals (Sweden)

Pedro Giovâni da Silva

2016-01-01

Full Text Available The Brazilian Atlantic Forest is one of the world's biodiversity hotspots, and is currently highly fragmented and disturbed due to human activities. Variation in environmental conditions in the Atlantic Forest can influence the distribution of species, which may show associations with some environmental features. Dung beetles (Coleoptera: Scarabaeinae are insects that act in nutrient cycling via organic matter decomposition and have been used for monitoring environmental changes. The aim of this study is to identify associations between the spatial distribution of dung beetle species and Atlantic Forest structure. The spatial distribution of some dung beetle species was associated with structural forest features. The number of species among the sampling sites ranged widely, and few species were found in all remnant areas. Principal coordinates analysis indicated that species composition, abundance and biomass showed a spatially structured distribution, and these results were corroborated by permutational multivariate analysis of variance. The indicator value index and redundancy analysis showed an association of several dung beetle species with some explanatory environmental variables related to Atlantic Forest structure. This work demonstrated the existence of a spatially structured distribution of dung beetles, with significant associations between several species and forest structure in Atlantic Forest remnants from Southern Brazil. Keywords: Beta diversity, Species composition, Species diversity, Spatial distribution, Tropical forest

Topographic asymmetry of the South Atlantic from global models of mantle flow and lithospheric stretching

Science.gov (United States)

Flament, Nicolas; Gurnis, Michael; Williams, Simon; Seton, Maria; Skogseid, Jakob; Heine, Christian; Müller, Dietmar

2014-05-01

The relief of the South Atlantic is characterized by elevated passive continental margins along southern Africa and eastern Brazil, and by the bathymetric asymmetry of the southern oceanic basin where the western flank is much deeper than the eastern flank. We investigate the origin of these topographic features in the present and over time since the Jurassic with a model of global mantle flow and lithospheric deformation. The model progressively assimilates plate kinematics, plate boundaries and lithospheric age derived from global tectonic reconstructions with deforming plates, and predicts the evolution of mantle temperature, continental crustal thickness, long-wavelength dynamic topography, and isostatic topography. Mantle viscosity and the kinematics of the opening of the South Atlantic are adjustable parameters in multiple model cases. Model predictions are compared to observables both for the present-day and in the past. Present-day predictions are compared to topography, mantle tomography, and an estimate of residual topography. Predictions for the past are compared to tectonic subsidence from backstripped borehole data along the South American passive margin, and to dynamic uplift as constrained by thermochronology in southern Africa. Comparison between model predictions and observations suggests that the first-order features of the topography of the South Atlantic are due to long-wavelength dynamic topography, rather than to asthenospheric processes. We find the uplift of southern Africa to be best reproduced with a lower mantle that is at least 40 times more viscous than the upper mantle.

Tsunami Forecasting in the Atlantic Basin

Science.gov (United States)

Knight, W. R.; Whitmore, P.; Sterling, K.; Hale, D. A.; Bahng, B.

2012-12-01

The mission of the West Coast and Alaska Tsunami Warning Center (WCATWC) is to provide advance tsunami warning and guidance to coastal communities within its Area-of-Responsibility (AOR). Predictive tsunami models, based on the shallow water wave equations, are an important part of the Center's guidance support. An Atlantic-based counterpart to the long-standing forecasting ability in the Pacific known as the Alaska Tsunami Forecast Model (ATFM) is now developed. The Atlantic forecasting method is based on ATFM version 2 which contains advanced capabilities over the original model; including better handling of the dynamic interactions between grids, inundation over dry land, new forecast model products, an optional non-hydrostatic approach, and the ability to pre-compute larger and more finely gridded regions using parallel computational techniques. The wide and nearly continuous Atlantic shelf region presents a challenge for forecast models. Our solution to this problem has been to develop a single unbroken high resolution sub-mesh (currently 30 arc-seconds), trimmed to the shelf break. This allows for edge wave propagation and for kilometer scale bathymetric feature resolution. Terminating the fine mesh at the 2000m isobath keeps the number of grid points manageable while allowing for a coarse (4 minute) mesh to adequately resolve deep water tsunami dynamics. Higher resolution sub-meshes are then included around coastal forecast points of interest. The WCATWC Atlantic AOR includes eastern U.S. and Canada, the U.S. Gulf of Mexico, Puerto Rico, and the Virgin Islands. Puerto Rico and the Virgin Islands are in very close proximity to well-known tsunami sources. Because travel times are under an hour and response must be immediate, our focus is on pre-computing many tsunami source "scenarios" and compiling those results into a database accessible and calibrated with observations during an event. Seismic source evaluation determines the order of model pre

Examining South Atlantic Subtropical Cyclone Anita using the Satellite-Enhanced Regional Downscaling for Applied Studies Hourly Outputs

Science.gov (United States)

Vaicberg, H.; Palmeira, A. C. P. A.; Nunes, A.

2017-12-01

Studies on South Atlantic cyclones are mainly compromised by scarcity of observations. Therefore, remote sensing and global (re) analysis products are usually employed in investigations of their evolution. However, the frequent use of global reanalysis might difficult the assessment of the characteristics of the cyclones found in South Atlantic. In that regard, studies on "subtropical" cyclones have been performed using the 25-km resolution, Satellite-enhanced Regional Downscaling for Applied Studies (SRDAS), a product developed at the Federal University of Rio de Janeiro in Brazil. In SRDAS, the Regional Spectral Model assimilates precipitation estimates from environmental satellites, while dynamically downscaling a global reanalysis using the spectral nudging technique to maintain the large-scale features in agreement with the regional model solution. The use of regional models in the downscaling of general circulation models provides more detailed information on weather and climate. As a way of illustrating the usefulness of SRDAS in the study of the subtropical South Atlantic cyclones, the subtropical cyclone Anita was selected because of its intensity. Anita developed near Brazilian south/southeast coast, with damages to local communities. Comparisons with available observations demonstrated the skill of SRDAS in simulating such an extreme event.

Modelling climate change effects on Atlantic salmon: Implications for mitigation in regulated rivers.

Science.gov (United States)

Sundt-Hansen, L E; Hedger, R D; Ugedal, O; Diserud, O H; Finstad, A G; Sauterleute, J F; Tøfte, L; Alfredsen, K; Forseth, T

2018-08-01

Climate change is expected to alter future temperature and discharge regimes of rivers. These regimes have a strong influence on the life history of most aquatic river species, and are key variables controlling the growth and survival of Atlantic salmon. This study explores how the future abundance of Atlantic salmon may be influenced by climate-induced changes in water temperature and discharge in a regulated river, and investigates how negative impacts in the future can be mitigated by applying different regulated discharge regimes during critical periods for salmon survival. A spatially explicit individual-based model was used to predict juvenile Atlantic salmon population abundance in a regulated river under a range of future water temperature and discharge scenarios (derived from climate data predicted by the Hadley Centre's Global Climate Model (GCM) HadAm3H and the Max Plank Institute's GCM ECHAM4), which were then compared with populations predicted under control scenarios representing past conditions. Parr abundance decreased in all future scenarios compared to the control scenarios due to reduced wetted areas (with the effect depending on climate scenario, GCM, and GCM spatial domain). To examine the potential for mitigation of climate change-induced reductions in wetted area, simulations were run with specific minimum discharge regimes. An increase in abundance of both parr and smolt occurred with an increase in the limit of minimum permitted discharge for three of the four GCM/GCM spatial domains examined. This study shows that, in regulated rivers with upstream storage capacity, negative effects of climate change on Atlantic salmon populations can potentially be mitigated by release of water from reservoirs during critical periods for juvenile salmon. Copyright © 2018. Published by Elsevier B.V.

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.

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.)

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.

Collaborative Research: Atlantic Ocean Tropical/Subtropical Processes from Seasonal to Decadal Time Scales: Model/Data, Model/Model Comparison and Model/Data Synthesis Through Assimilation

Science.gov (United States)

Malannotte-Rizzoli, Paola

2003-01-01

The effort of this first year of research has been focused on the assimilation of TOPEX/Poseidon altimetric data into a primitive equation model of the Atlantic tropical/subtropical circulation. A reduced-rank, stationary Kalman filter has been constructed to assimilate the altimetric sea surface height anomaly (SHA) into the model. The goal is to assess how the inter-hemispheric transports between the Atlantic subtropics and tropics are affected by the assimilation and how the subsurface thermocline structure , and its variability ,is dynamically constrained by the SHA. The model is a reduced-gravity primitive equation GCM of the upper Atlantic Ocean between 30 S and 30 N. The assimilation scheme is an approximation to the extended Kalman filter in which the error covariances of the state estimates are calculated only in a reduced- dimension subspace. The subspace is defined by the leading empirical orthogonal functions calculated from an unconstrained model calculation. Both an identical twin experiment using simulated SHA observations and assimilation of the real TOPEX data were performed. Results from the twin experiments demonstrate the ability of the method to constrain the ocean circulation and the subsurface temperature structure. The impact on the subsurface temperature structure of TOPEX assimilation was assessed using data from expandable bathythermographs. This showed a substantial improvement in the estimated temperature variability only within 13 degrees in latitude around the equator. The impact of TOPEX SHA assimilation on zonally integrated meridional transport across different latitudes was also estimated. Again within 13 degrees from the equator both the mean amplitude and interannual variability of the surface and subsurface transports were significantly enhanced, while the transports were insensitive to the assimilation in the subtropics.

Modeling the impact of iron and phosphorus limitations on nitrogen fixation in the Atlantic Ocean

Directory of Open Access Journals (Sweden)

R. R. Hood

2007-07-01

Full Text Available The overarching goal of this study is to simulate subsurface N* (sensu, Gruber and Sarmiento, 1997; GS97 anomaly patterns in the North Atlantic Ocean and determine the basin wide rates of N₂-fixation that are required to do so. We present results from a new Atlantic implementation of a coupled physical-biogeochemical model that includes an explicit, dynamic representation of N₂-fixation with light, nitrogen, phosphorus and iron limitations, and variable stoichiometric ratios. The model is able to reproduce nitrogen, phosphorus and iron concentration variability to first order. The latter is achieved by incorporating iron deposition directly into the model's detrital iron compartment which allows the model to reproduce sharp near surface gradients in dissolved iron concentration off the west coast of Africa and deep dissolved iron concentrations that have been observed in recent observational studies. The model can reproduce the large scale N* anomaly patterns but requires relatively high rates of surface nitrogen fixation to do so (1.8×10¹² moles N yr⁻¹ from 10° N–30° N, 3.4×10¹² moles N yr⁻¹ from 25° S–65° N. In the model the surface nitrogen fixation rate patterns are not co-located with subsurface gradients in N*. Rather, the fixed nitrogen is advected away from its source prior to generating a subsurface N* anomaly. Changes in the phosphorus remineralization rate (relative to nitrogen linearly determine the surface nitrogen fixation rate because they change the degree of phosphorus limitation, which is the dominant limitation in the Atlantic in the model. Phosphorus remineralization rate must be increased by about a factor of 2 (relative to nitrogen in order to generate subsurface N* anomalies that are comparable to the observations. We conclude that N₂-fixation rate estimates for the Atlantic (and globally may need to be revised upward, which

Latest Cretaceous climatic and environmental change in the South Atlantic region

Science.gov (United States)

Woelders, L.; Vellekoop, J.; Kroon, D.; Smit, J.; Casadío, S.; Prámparo, M. B.; Dinarès-Turell, J.; Peterse, F.; Sluijs, A.; Lenaerts, J. T. M.; Speijer, R. P.

2017-05-01

Latest Maastrichtian climate change caused by Deccan volcanism has been invoked as a cause of mass extinction at the Cretaceous-Paleogene (K-Pg) boundary ( 66.0 Ma). Yet late Maastrichtian climate and ecological changes are poorly documented, in particular on the Southern Hemisphere. Here we present upper Maastrichtian-lower Danian climate and biotic records from the Bajada del Jagüel (BJ) shelf site (Neuquén Basin, Argentina), employing the TEX86 paleothermometer, marine palynology (dinoflagellate cysts), and micropaleontology (foraminifera). These records are correlated to the astronomically tuned Ocean Drilling Program Site 1262 (Walvis Ridge). Collectively, we use these records to assess climatic and ecological effects of Deccan volcanism in the Southern Atlantic region. Both the TEX86-based sea surface temperature (SST) record at BJ and the bulk carbonate δ18O-based SST record of Site 1262 show a latest Maastrichtian warming of 2.5-4°C, at 450 to 150 kyr before the K-Pg boundary, coinciding with the a large Deccan outpouring phase. Benthic foraminiferal and dinocyst assemblage changes indicate that this warming resulted in enhanced runoff and stratification of the water column, likely resulting from more humid climate conditions in the Neuquén Basin. These climate conditions could have been caused by an expanding and strengthening thermal low over the South American continent. Biotic changes in response to late Maastrichtian environmental changes are rather limited, when compared to the major turnovers observed at many K-Pg boundary sites worldwide. This suggests that environmental perturbations during the latest Maastrichtian warming event were less severe than those following the K-Pg boundary impact.

Modeling the drift of massive icebergs to the subtropical North Atlantic

Science.gov (United States)

Condron, A.; Hill, J. C.

2013-12-01

New evidence from high-resolution seafloor bathymetry data indicates that massive (>300m thick) icebergs from the Laurentide Ice Sheet (LIS) drifted south to the tip of Florida during the last deglaciation. This finding is particularly exciting as it contradicts evidence from marine sediments that icebergs were mainly confined to the subpolar North Atlantic (50 - 70N) at this time. Indeed, the freshwater released from icebergs melting in the subpolar gyre is repeatedly cited as a main trigger for a slow-down of the Atlantic MOC in the past, and the possible cause of any climate cooling related to the melting of the Greenland Ice Sheet in the future. Using a sophisticated iceberg model (MITberg), coupled to a high (18-km; 1/6 deg.) resolution ocean model (MITgcm), we investigate the ocean circulation dynamics required to allow icebergs to drift to the southern tip of Florida. We find that icebergs only reach this location if they turn right at the Grand Banks of Newfoundland, and stay inshore of the Gulf Stream all the way to Florida. Modern-day circulation dynamics do not readily allow this to happen as cold, southward flowing, Labrador Current Water (important for iceberg survival) has little penetration south of Cape Hatteras. However, when a liquid meltwater flood is released from Hudson Bay at the same time, icebergs are rapidly transported (inshore of the Gulf Stream) in a narrow, buoyant, coastal current all the way to southern Florida. The meltwater and icebergs result in a significant freshening of the subtropical North Atlantic and weaken the strength of the Gulf Stream, suggesting such an event would have a large cooling effect on climate. We are only able to simulate the flow of meltwater and icebergs to the subtropics by modeling ocean circulation at a resolution that is 5 - 10 times higher than the majority of existing paleoclimate models; at lower resolutions the narrow, coastal boundary currents important for iceberg transport to the subtropics are

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

Connecting Atlantic temperature variability and biological cycling in two earth system models

Science.gov (United States)

Gnanadesikan, Anand; Dunne, John P.; Msadek, Rym

2014-05-01

Connections between the interdecadal variability in North Atlantic temperatures and biological cycling have been widely hypothesized. However, it is unclear whether such connections are due to small changes in basin-averaged temperatures indicated by the Atlantic Multidecadal Oscillation (AMO) Index, or whether both biological cycling and the AMO index are causally linked to changes in the Atlantic Meridional Overturning Circulation (AMOC). We examine interdecadal variability in the annual and month-by-month diatom biomass in two Earth System Models with the same formulations of atmospheric, land, sea ice and ocean biogeochemical dynamics but different formulations of ocean physics and thus different AMOC structures and variability. In the isopycnal-layered ESM2G, strong interdecadal changes in surface salinity associated with changes in AMOC produce spatially heterogeneous variability in convection, nutrient supply and thus diatom biomass. These changes also produce changes in ice cover, shortwave absorption and temperature and hence the AMO Index. Off West Greenland, these changes are consistent with observed changes in fisheries and support climate as a causal driver. In the level-coordinate ESM2M, nutrient supply is much higher and interdecadal changes in diatom biomass are much smaller in amplitude and not strongly linked to the AMO index.

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.

Environmental change studies in the Caspian Sea and the north-east Atlantic Ocean

International Nuclear Information System (INIS)

Povinec, P.; Oregioni, B.; GASTAUD, J.

2002-01-01

Caspian Sea and NE Atlantic water profiles were investigated for radionuclide content. Radionuclide data on the water samples collected in 1995 and 1996 in the Caspian Sea show a rapid exchange of water masses in the two deep basins (the Central and Southern Basins). The main source of radionuclides is global fallout. In the NE Atlantic Ocean elevated concentrations of 3 H and 4 C were observed at medium depths (2000-3000 m) which could be explained by high latitude injection processes. (author)

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...

A continuous time delay-difference type model (CTDDM) applied to stock assessment of the southern Atlantic albacore Thunnus alalunga

Institute of Scientific and Technical Information of China (English)

LIAO Baochao; LIU Qun; ZHANG Kui; Abdul BASET; Aamir Mahmood MEMON; Khadim Hussain MEMON; HAN Yanan

2016-01-01

A continuous time delay-difference model (CTDDM) has been established that considers continuous time delays of biological processes.The southern Atlantic albacore (Thunnus alalunga) stock is the one of the commercially important tuna population in the marine world.The age structured production model (ASPM) and the surplus production model (SPM) have already been used to assess the albacore stock.However,the ASPM requires detailed biological information and the SPM lacks the biological realism.In this study,we focus on applying a CTDDM to the southern Atlantic albacore (T.alalunga) species,which provides an alternative method to assess this fishery.It is the first time that CTDDM has been provided for assessing the Atlantic albacore (T.alalunga) fishery.CTDDM obtained the 80％ confidence interval of MSY (maximum sustainable yield) of(21510 t,23118 t).The catch in 2011 (24100 t) is higher than the MSY values and the relative fishing mortality ratio (F2011/FMSY) is higher than 1.0.The results of CTDDM were analyzed to verify the proposed methodology and provide reference information for the sustainable management of the southern Atlantic albacore stock.The CTDDM treats the recruitment,the growth,and the mortality rates as all varying continuously over time and fills gaps between ASPM and SPM in this stock assessment.

Phytoplankton biomass dynamics and environmental variables around the Rocas Atoll Biological Reserve, South Atlantic

Directory of Open Access Journals (Sweden)

Marina Cavalcanti Jales

2015-12-01

Full Text Available Abstract The Rocas Atoll Biological Reserve is located in the Atlantic Ocean, at 3º 51' S and 33º 49' W. It lies 143 nautical miles from the City of Natal, Rio Grande do Norte (Brazil. The purpose of this study was to analyze the hydrology, water masses, currents and chlorophyll a content to determine the dynamics of phytoplankton biomass around the Rocas Atoll. Samples were collected in July 2010 in the area around the Atoll, using the Research Vessel Cruzeiro do Sul of the Brazilian Navy. Two transects were established according to the surface currents, one of which at the southeast of the Atoll (SE and the other at norwest (NW. Three collection points were determined on each of these transects. Samples were collected at different depths (surface and DCM - Deep Chlorophyll Maximum and different times (day and night. According to PCA (Principal Component Analysis, the nutrients analyzed, DIN (dissolved inorganic nitrogen, DIP (dissolved inorganic phosphorus and silicate, were inversely correlated with temperature and dissolved oxygen. Most environmental variables showed a significant increase due to the turbulence on the Northwest transect. There was an increase in the concentration of chlorophyll a and nutrients when the temperature and oxygen in the mixed layer was reduced due to the influence of the SACW (South Atlantic Central Water. Despite the increase observed in some variables such as nutrient salts and chlorophyll a, the temperature in the mixed layer attained a mean value of 23.23 ºC due to the predominance of Tropical Water. The increase of the phytoplankton biomass on the NW transect was, therefore, caused by the "island effect" and not by upwelling.

ProAtlantic - The Atlantic Checkpoint - Data Availability and Adequacy in the Atlantic Basin

Science.gov (United States)

McGrath, F.

2017-12-01

DG MAREs Atlantic Checkpoint is a basin scale wide monitoring system assessment activity based upon targeted end-user applications. It is designed to be a benchmark for the assessment of hydrographic, geological, habitat, climate and fisheries data existence and availability in the Atlantic basin. DG MAREs Atlantic Checkpoint service will be delivered by the ProAtlantic project. The objective of this project is to investigate, through appropriate methodologies in the framework of 11 key marine challenges, how current international and national data providers - e.g. EMODNet, Copernicus - meet the requirements of the stakeholders and deliver fit for purpose data. By so doing, the main thematic and geographic gaps will be readily identified in the Atlantic basin for future consideration by DG MARE. For each challenge, specific web products in the form of maps, metadata, spreadsheets and reports will be delivered. These products are not an end by themselves but rather a means of showing whether data were available, let alone accessible. For example, the Fisheries Impact Challenge outputs include data grids (VMS/Seabed) and data adequacy reports. Production of gridded data layers in order to show the extent of fisheries impact on the seafloor involved the identification, acquisition and collation of data sources for the required data types (VMS/Seabed/Habitats Data) in the Atlantic basin. The resulting spatial coverage of these grids indicates the relatively low level of data availability and adequacy across the Atlantic basin. Aside from the data delivered by programmes such as EMODNet and Copernicus, there are a lot of initiatives by regional bodies such as OSPAR and ICES that consist of assembling and disseminating data to address specific issues. Several international projects have delivered research, data collection, and networking around several of the Atlantic Checkpoint challenge topics, namely MPAs, renewable energy assessment, seabed mapping, oil spill

Modulation of extremes in the Atlantic region by modes of climate variability/change: A mechanistic coupled regional model study

Energy Technology Data Exchange (ETDEWEB)

Saravanan, Ramalingam [Texas A & M Univ., College Station, TX (United States)

2015-01-09

During the course of this project, we have accomplished the following: 1) Explored the parameter space of component models to minimize regional model bias 2) Assessed the impact of air-sea interaction on hurricanes, focusing in particular on the role of the oceanic barrier layer 3) Contributed to the activities of the U.S. CLIVAR Hurricane Working Group 4) Assessed the impact of lateral and lower boundary conditions on extreme flooding events in the U.S. Midwest in regional model simulations 5) Analyzed the concurrent impact of El Niño-Southern Oscillation and Atlantic Meridional Mode on Atlantic Hurricane activity using observations and regional model simulations

Genetic factors have a major effect on growth, number of vertebrae and otolith shape in Atlantic herring (Clupea harengus).

Science.gov (United States)

Berg, Florian; Almeland, Oda W; Skadal, Julie; Slotte, Aril; Andersson, Leif; Folkvord, Arild

2018-01-01

Atlantic herring, Clupea harengus, have complex population structures. Mixing of populations is known, but the extent of connectivity is still unclear. Phenotypic plasticity results in divergent phenotypes in response to environmental factors. A marked salinity gradient occurs from Atlantic Ocean (salinity 35) into the Baltic Sea (salinity range 2-12). Herring from both habitats display phenotypic and genetic variability. To explore how genetic factors and salinity influence phenotypic traits like growth, number of vertebrae and otolith shape an experimental population consisting of Atlantic purebreds and Atlantic/Baltic F1 hybrids were incubated and co-reared at two different salinities, 16 and 35, for three years. The F1-generation was repeatedly sampled to evaluate temporal variation. A von Bertalanffy growth model indicated that reared Atlantic purebreds had a higher maximum length (26.2 cm) than Atlantic/Baltic hybrids (24.8 cm) at salinity 35, but not at salinity 16 (25.0 and 24.8 cm, respectively). In contrast, Atlantic/Baltic hybrids achieved larger size-at-age than the wild caught Baltic parental group. Mean vertebral counts and otolith aspect ratios were higher for reared Atlantic purebreds than Atlantic/Baltic hybrids, consistent with the differences between parental groups. There were no significant differences in vertebral counts and otolith aspect ratios between herring with the same genotype but raised in different salinities. A Canonical Analysis of Principal Coordinates was applied to analyze the variation in wavelet coefficients that described otolith shape. The first discriminating axis identified the differences between Atlantic purebreds and Atlantic/Baltic hybrids, while the second axis represented salinity differences. Assigning otoliths based on genetic groups (Atlantic purebreds vs. Atlantic/Baltic hybrids) yielded higher classification success (~90%) than based on salinities (16 vs. 35; ~60%). Our results demonstrate that otolith shape and

Glacial climate sensitivity to different states of the Atlantic Meridional Overturning Circulation: results from the IPSL model

Directory of Open Access Journals (Sweden)

M. Kageyama

2009-09-01

Full Text Available Paleorecords from distant locations on the globe show rapid and large amplitude climate variations during the last glacial period. Here we study the global climatic response to different states of the Atlantic Meridional Overturning Circulation (AMOC as a potential explanation for these climate variations and their possible connections. We analyse three glacial simulations obtained with an atmosphere-ocean coupled general circulation model and characterised by different AMOC strengths (18, 15 and 2 Sv resulting from successive ~0.1 Sv freshwater perturbations in the North Atlantic. These AMOC states suggest the existence of a freshwater threshold for which the AMOC collapses. A weak (18 to 15 Sv AMOC decrease results in a North Atlantic and European cooling. This cooling is not homogeneous, with even a slight warming over the Norwegian Sea. Convection in this area is active in both experiments, but surprisingly stronger in the 15 Sv simulation, which appears to be related to interactions with the atmospheric circulation and sea-ice cover. Far from the North Atlantic, the climatic response is not significant. The climate differences for an AMOC collapse (15 to 2 Sv are much larger and of global extent. The timing of the climate response to this AMOC collapse suggests teleconnection mechanisms. Our analyses focus on the North Atlantic and surrounding regions, the tropical Atlantic and the Indian monsoon region. The North Atlantic cooling associated with the AMOC collapse induces a cyclonic atmospheric circulation anomaly centred over this region, which modulates the eastward advection of cold air over the Eurasian continent. This can explain why the cooling is not as strong over western Europe as over the North Atlantic. In the Tropics, the southward shift of the Inter-Tropical Convergence Zone appears to be strongest over the Atlantic and Eastern Pacific and results from an adjustment of the atmospheric and oceanic heat transports. Finally, the

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.

Management of Atlantic walrus (Odobenus rosmarus rosmarus in the arctic Atlantic

Directory of Open Access Journals (Sweden)

Øystein Wiig

2014-12-01

of protection afforded to walrus habitat in many areas depends entirely on the rigor with which the Environmental Impact Assessments are conducted. Basic information on walrus such as numbers and stock discreteness is often lacking and sufficient lead-time is required to collect baseline data. Moreover, although most environmental protection legislation considers ‘cumulative impacts’, practical application remains problematic. The effectiveness of environmental protection regulations depends on industry compliance and the management authorities’ ability to enforce compliance. Because walrus are found in remote locations, enforcement remains a challenge. Increased human activity allowed by the current change in distribution and quality of arctic sea ice poses new threats to walrus if not well regulated. International agreements have varying importance for management within and among member states. Regulations governing international trade serve to identify illegally obtained products and to encourage range states to have a sustainable quota system. International cooperation in information sharing has had clear benefits for management of walruses in the past. The maintenance and expansion of these international efforts will improve the management of Atlantic walruses in the future.

Wintering habitat model for the North Atlantic Right Whale (Eubalaena glacialis) in the southeastern United States.

Science.gov (United States)

Gowan, Timothy A; Ortega-Ortiz, Joel G

2014-01-01

The coastal waters off the southeastern United States (SEUS) are a primary wintering ground for the endangered North Atlantic right whale (Eubalaena glacialis), used by calving females along with other adult and juvenile whales. Management actions implemented in this area for the recovery of the right whale population rely on accurate habitat characterization and the ability to predict whale distribution over time. We developed a temporally dynamic habitat model to predict wintering right whale distribution in the SEUS using a generalized additive model framework and aerial survey data from 2003/2004 through 2012/2013. We built upon previous habitat models for right whales in the SEUS and include data from new aerial surveys that extend the spatial coverage of the analysis, particularly in the northern portion of this wintering ground. We summarized whale sightings, survey effort corrected for probability of whale detection, and environmental data at a semimonthly resolution. Consistent with previous studies, sea surface temperature (SST), water depth, and survey year were significant predictors of right whale relative abundance. Additionally, distance to shore, distance to the 22°C SST isotherm, and an interaction between time of year and latitude (to account for the latitudinal migration of whales) were also selected in the analysis presented here. Predictions from the model revealed that the location of preferred habitat differs within and between years in correspondence with variation in environmental conditions. Although cow-calf pairs were rarely sighted in the company of other whales, there was minimal evidence that the preferred habitat of cow-calf pairs was different than that of whale groups without calves at the scale of this study. The results of this updated habitat model can be used to inform management decisions for a migratory species in a dynamic oceanic environment.

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

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.

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.

2015-12-01

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.

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.

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.

76 FR 72383 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures

Science.gov (United States)

2011-11-23

...-BA17 Atlantic Highly Migratory Species; Atlantic Shark Management Measures AGENCY: National Marine... plan (FMP) amendment that would consider catch shares for the Atlantic shark fisheries. The comment... potential catch shares programs in the Atlantic shark fisheries. Additionally, NMFS is extending the comment...

Marine environmental monitoring related to sea disposal of radioactive waste in the NE Atlantic Ocean

International Nuclear Information System (INIS)

Bettencourt, A.O.; Elias, M.D.T.; Ferrador, G.C.

1988-01-01

Reference is made to the sea disposal of packaged radioactive waste in the NE Atlantic and to the role of the OCDE Nuclear Energy Agency (NEA) since 1967, in the dumping operations. The objectives of marine environmental monitoring in relation to sea disposal of radioactive wastes are described as well as the coordinated research and environmental surveillance programme (CRESP) developed within NEA frame. The Portuguese on-going programme in this field is presented and the results concerning measurements of 239+240 Pu, 238 Pu, 241 Am and 137 Cs in samples of water, sediments and fish collected at Madeira and Continental Portuguese coasts, are discussed. It was observed that these radionuclides concentrations are lower for deep-sea fishes than for the shallow-water ones. The obtained results are compared with those found in the literature. From the observation of the large spectrum of results available, it can be concluded that no generalized contamination of the marine environment due to the sea dumping of radioactive wastes if observed at present. On the other hand, there is an interest in pursuing analyses of deep-sea fish with the aim of early detection of any possible modifications in the actual levels of radioactivity in the marine environment. (author) [pt

Assessing the quality of bottom water temperatures from the Finite-Volume Community Ocean Model (FVCOM) in the Northwest Atlantic Shelf region

Science.gov (United States)

Li, Bai; Tanaka, Kisei R.; Chen, Yong; Brady, Damian C.; Thomas, Andrew C.

2017-09-01

The Finite-Volume Community Ocean Model (FVCOM) is an advanced coastal circulation model widely utilized for its ability to simulate spatially and temporally evolving three-dimensional geophysical conditions of complex and dynamic coastal regions. While a body of literature evaluates model skill in surface fields, independent studies validating model skill in bottom fields over large spatial and temporal scales are scarce because these fields cannot be remotely sensed. In this study, an evaluation of FVCOM skill in modeling bottom water temperature was conducted by comparison to hourly in situ observed bottom temperatures recorded by the Environmental Monitors on Lobster Traps (eMOLT), a program that attached thermistors to commercial lobster traps from 2001 to 2013. Over 2 × 106 pairs of FVCOM-eMOLT records were evaluated by a series of statistical measures to quantify accuracy and precision of the modeled data across the Northwest Atlantic Shelf region. The overall comparison between modeled and observed data indicates reliable skill of FVCOM (r2 = 0.72; root mean squared error = 2.28 °C). Seasonally, the average absolute errors show higher model skill in spring, fall and winter than summer. We speculate that this is due to the increased difficulty of modeling high frequency variability in the exact position of the thermocline and frontal zones. The spatial patterns of the residuals suggest that there is improved similarity between modeled and observed data at higher latitudes. We speculate that this is due to increased tidal mixing at higher latitudes in our study area that reduces stratification in winter, allowing improved model accuracy. Modeled bottom water temperatures around Cape Cod, the continental shelf edges, and at one location at the entrance to Penobscot Bay were characterized by relatively high errors. Constraints for future uses of FVCOM bottom water temperature are provided based on the uncertainties in temporal-spatial patterns. This study is

Deep-sea benthic habitats modeling and mapping in a NE Atlantic seamount (Galicia Bank)

Science.gov (United States)

Serrano, A.; González-Irusta, J. M.; Punzón, A.; García-Alegre, A.; Lourido, A.; Ríos, P.; Blanco, M.; Gómez-Ballesteros, M.; Druet, M.; Cristobo, J.; Cartes, J. E.

2017-08-01

This study presents the results of seafloor habitat identification and mapping of a NE Atlantic deep seamount. An ;assemble first, predict later; approach has been followed to identify and map the benthic habitats of the Galicia Bank (NW Iberian). Biotic patterns inferred from the survey data have been used to drive the definition of benthic assemblages using multivariate tools. Eight assemblages, four hard substrates and four sedimentary ones, have been described from a matrix of structural species. Distribution of these assemblages was correlated with environmental factors (multibeam and backscatter data) using binomial GAMs. Finally, the distribution model of each assemblage was applied to produce continuous maps and pooled in a final map with the distribution of the main benthic habitats. Depth and substrate type are key factors when determining soft bottom communities, whereas rocky habitat distribution is mainly explained by rock slope and orientation. Enrichment by northern water masses (LSW) arriving to GB and possible zooplankton biomass increase at vertical-steep walls by ;bottom trapping; can explain the higher diversity of habitat providing filter-feeders at slope rocky breaks. These results concerning vulnerable species and habitats, such as Lophelia and Madrepora communities and black and bamboo coral aggregations were the basis of the Spanish proposal of inclusion within the Natura 2000 network. The aim of the present study was to establish the scientific criteria needed for managing and protecting those environmental values.

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.)

78 FR 54195 - Atlantic Highly Migratory Species; Atlantic Commercial Shark Fisheries

Science.gov (United States)

2013-09-03

.... 110831548-3536-02] RIN 0648-XC836 Atlantic Highly Migratory Species; Atlantic Commercial Shark Fisheries...) dressed weight (dw) of non-blacknose small coastal shark (SCS) quota from the Atlantic region to the Gulf... Atlantic shark permitted vessels. DATES: The quota transfer is effective from September 2, 2013 until...

Environmental Satellite Models for a Macroeconomic Model

International Nuclear Information System (INIS)

Moeller, F.; Grinderslev, D.; Werner, M.

2003-01-01

To support national environmental policy, it is desirable to forecast and analyse environmental indicators consistently with economic variables. However, environmental indicators are physical measures linked to physical activities that are not specified in economic models. One way to deal with this is to develop environmental satellite models linked to economic models. The system of models presented gives a frame of reference where emissions of greenhouse gases, acid gases, and leaching of nutrients to the aquatic environment are analysed in line with - and consistently with - macroeconomic variables. This paper gives an overview of the data and the satellite models. Finally, the results of applying the model system to calculate the impacts on emissions and the economy are reviewed in a few illustrative examples. The models have been developed for Denmark; however, most of the environmental data used are from the CORINAIR system implemented in numerous countries

Alleviating tropical Atlantic sector biases in the Kiel climate model by enhancing horizontal and vertical atmosphere model resolution: climatology and interannual variability

Science.gov (United States)

Harlaß, Jan; Latif, Mojib; Park, Wonsun

2018-04-01

We investigate the quality of simulating tropical Atlantic (TA) sector climatology and interannual variability in integrations of the Kiel climate model (KCM) with varying atmosphere model resolution. The ocean model resolution is kept fixed. A reasonable simulation of TA sector annual-mean climate, seasonal cycle and interannual variability can only be achieved at sufficiently high horizontal and vertical atmospheric resolution. Two major reasons for the improvements are identified. First, the western equatorial Atlantic westerly surface wind bias in spring can be largely eliminated, which is explained by a better representation of meridional and especially vertical zonal momentum transport. The enhanced atmospheric circulation along the equator in turn greatly improves the thermal structure of the upper equatorial Atlantic with much reduced warm sea surface temperature (SST) biases. Second, the coastline in the southeastern TA and steep orography are better resolved at high resolution, which improves wind structure and in turn reduces warm SST biases in the Benguela upwelling region. The strongly diminished wind and SST biases at high atmosphere model resolution allow for a more realistic latitudinal position of the intertropical convergence zone. Resulting stronger cross-equatorial winds, in conjunction with a shallower thermocline, enable a rapid cold tongue development in the eastern TA in boreal spring. This enables simulation of realistic interannual SST variability and its seasonal phase locking in the KCM, which primarily is the result of a stronger thermocline feedback. Our findings suggest that enhanced atmospheric resolution, both vertical and horizontal, could be a key to achieving more realistic simulation of TA climatology and interannual variability in climate models.

Assessment of organochlorine pesticide residues in Atlantic Rain Forest fragments, Rio de Janeiro, Brazil

Energy Technology Data Exchange (ETDEWEB)

Soares Quinete, Natalia, E-mail: nataliaquinete@yahoo.com.br [Instituto Nacional de Tecnologia, Departamento de Quimica Analitica, Laboratorio de Quimica Analitica e Metrologia em Quimica, Av. Venezuela, 82 - Rio de Janeiro, RJ 20081-312 (Brazil); Santos de Oliveira, Elba dos [Instituto Nacional de Tecnologia, Departamento de Energia, Av. Venezuela, 82 - Rio de Janeiro, RJ 20081-312 (Brazil); Fernandes, Daniella R. [Universidade Federal do Rio de Janeiro, Instituto de Quimica, Departamento de Quimica Analitica, CT - Bloco A, Cidade Universitaria, 21941-909 - Rio de Janeiro (Brazil); Souza Avelar, Andre de [Universidade Federal do Rio de Janeiro, Departamento de Geografia, Instituto de Geociencias, CCMN, Bloco F, Cidade Universitaria, 21941-919 - Rio de Janeiro (Brazil); Erthal Santelli, Ricardo [Universidade Federal do Rio de Janeiro, Instituto de Quimica, Departamento de Quimica Analitica, CT - Bloco A, Cidade Universitaria, 21941-909 - Rio de Janeiro (Brazil)

2011-12-15

A superficial water quality survey in a watershed of the Paraiba do Sul River, the main water supply for the most populated cities of southeastern Brazil, was held in order to assess the impact of the expansion of agricultural activity in the near border of the Atlantic Rain Forest. The aim of this study was to investigate the presence of priority organochlorine pollutants in soils and superficial waters of Atlantic rainforest fragments in Teresopolis, Rio de Janeiro State. Soil sample preparations were compared by using ultrasound, microwave assisted extraction and Soxhlet extraction. Recoveries of matrix spiked samples ranged from 70 to 130%. Analysis of a certified soil material showed recoveries ranging from 71 to 234%. Although low concentrations of organochlorine residues were found in water and soil samples, this area is of environmental importance and concern, thus demanding a monitoring program of its compartments. - Highlights: > The organochlorine pollutants occurrence in the Atlantic Rain Forest was investigated. > PARNASO was considered a control area of environmental quality. > Extractions methods were compared for typical C-rich soils samples from Brazil. > Low concentrations of organochlorine residues were found in water and soil samples. > A monitoring program is demanded due to the environmental importance of the area. - The occurrence of organochlorine pollutants in soils of the Atlantic rainforest fragments in Rio de Janeiro, Brazil demands a monitoring program of its compartments.

Assessment of organochlorine pesticide residues in Atlantic Rain Forest fragments, Rio de Janeiro, Brazil

International Nuclear Information System (INIS)

Soares Quinete, Natalia; Santos de Oliveira, Elba dos; Fernandes, Daniella R.; Souza Avelar, Andre de; Erthal Santelli, Ricardo

2011-01-01

A superficial water quality survey in a watershed of the Paraiba do Sul River, the main water supply for the most populated cities of southeastern Brazil, was held in order to assess the impact of the expansion of agricultural activity in the near border of the Atlantic Rain Forest. The aim of this study was to investigate the presence of priority organochlorine pollutants in soils and superficial waters of Atlantic rainforest fragments in Teresopolis, Rio de Janeiro State. Soil sample preparations were compared by using ultrasound, microwave assisted extraction and Soxhlet extraction. Recoveries of matrix spiked samples ranged from 70 to 130%. Analysis of a certified soil material showed recoveries ranging from 71 to 234%. Although low concentrations of organochlorine residues were found in water and soil samples, this area is of environmental importance and concern, thus demanding a monitoring program of its compartments. - Highlights: → The organochlorine pollutants occurrence in the Atlantic Rain Forest was investigated. → PARNASO was considered a control area of environmental quality. → Extractions methods were compared for typical C-rich soils samples from Brazil. → Low concentrations of organochlorine residues were found in water and soil samples. → A monitoring program is demanded due to the environmental importance of the area. - The occurrence of organochlorine pollutants in soils of the Atlantic rainforest fragments in Rio de Janeiro, Brazil demands a monitoring program of its compartments.

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.

Preparatory selection of sterilization regime for canned Natural Atlantic Mackerel with oil based on developed mathematical models of the process

Directory of Open Access Journals (Sweden)

Maslov A. A.

2016-12-01

Full Text Available Definition of preparatory parameters for sterilization regime of canned "Natural Atlantic Mackerel with Oil" is the aim of current study. PRSC software developed at the department of automation and computer engineering is used for preparatory selection. To determine the parameters of process model, in laboratory autoclave AVK-30M the pre-trial process of sterilization and cooling in water with backpressure of canned "Natural Atlantic Mackerel with Oil" in can N 3 has been performed. Gathering information about the temperature in the autoclave sterilization chamber and the can with product has been carried out using Ellab TrackSense PRO loggers. Due to the obtained information three transfer functions for the product model have been identified: in the least heated area of autoclave, the average heated and the most heated. In PRSC programme temporary temperature dependences in the sterilization chamber have been built using this information. The model of sterilization process of canned "Natural Atlantic Mackerel with Oil" has been received after the pre-trial process. Then in the automatic mode the sterilization regime of canned "Natural Atlantic Mackerel with Oil" has been selected using the value of actual effect close to normative sterilizing effect (5.9 conditional minutes. Furthermore, in this study step-mode sterilization of canned "Natural Atlantic Mackerel with Oil" has been selected. Utilization of step-mode sterilization with the maximum temperature equal to 125 °C in the sterilization chamber allows reduce process duration by 10 %. However, the application of this regime in practice requires additional research. Using the described approach based on the developed mathematical models of the process allows receive optimal step and variable canned food sterilization regimes with high energy efficiency and product quality.

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

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

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.)

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.)

Adequacy assessment of mathematical models in the dynamics of litter decomposition in a tropical forest Mosaic Atlantic, in southeastern Brazil

Directory of Open Access Journals (Sweden)

FP. Nunes

Full Text Available The study of litter decomposition and nutrient cycling is essential to know native forests structure and functioning. Mathematical models can help to understand the local and temporal litter fall variations and their environmental variables relationships. The objective of this study was test the adequacy of mathematical models for leaf litter decomposition in the Atlantic Forest in southeastern Brazil. We study four native forest sites in Parque Estadual do Rio Doce, a Biosphere Reserve of the Atlantic, which were installed 200 bags of litter decomposing with 20×20 cm nylon screen of 2 mm, with 10 grams of litter. Monthly from 09/2007 to 04/2009, 10 litterbags were removed for determination of the mass loss. We compared 3 nonlinear models: 1 – Olson Exponential Model (1963, which considers the constant K, 2 – Model proposed by Fountain and Schowalter (2004, 3 – Model proposed by Coelho and Borges (2005, which considers the variable K through QMR, SQR, SQTC, DMA and Test F. The Fountain and Schowalter (2004 model was inappropriate for this study by overestimating decomposition rate. The decay curve analysis showed that the model with the variable K was more appropriate, although the values of QMR and DMA revealed no significant difference (p> 0.05 between the models. The analysis showed a better adjustment of DMA using K variable, reinforced by the values of the adjustment coefficient (R2. However, convergence problems were observed in this model for estimate study areas outliers, which did not occur with K constant model. This problem can be related to the non-linear fit of mass/time values to K variable generated. The model with K constant shown to be adequate to describe curve decomposition for separately areas and best adjustability without convergence problems. The results demonstrated the adequacy of Olson model to estimate tropical forest litter decomposition. Although use of reduced number of parameters equaling the steps of the

Adequacy assessment of mathematical models in the dynamics of litter decomposition in a tropical forest Mosaic Atlantic, in southeastern Brazil.

Science.gov (United States)

Nunes, F P; Garcia, Q S

2015-05-01

The study of litter decomposition and nutrient cycling is essential to know native forests structure and functioning. Mathematical models can help to understand the local and temporal litter fall variations and their environmental variables relationships. The objective of this study was test the adequacy of mathematical models for leaf litter decomposition in the Atlantic Forest in southeastern Brazil. We study four native forest sites in Parque Estadual do Rio Doce, a Biosphere Reserve of the Atlantic, which were installed 200 bags of litter decomposing with 20 × 20 cm nylon screen of 2 mm, with 10 grams of litter. Monthly from 09/2007 to 04/2009, 10 litterbags were removed for determination of the mass loss. We compared 3 nonlinear models: 1 - Olson Exponential Model (1963), which considers the constant K, 2 - Model proposed by Fountain and Schowalter (2004), 3 - Model proposed by Coelho and Borges (2005), which considers the variable K through QMR, SQR, SQTC, DMA and Test F. The Fountain and Schowalter (2004) model was inappropriate for this study by overestimating decomposition rate. The decay curve analysis showed that the model with the variable K was more appropriate, although the values of QMR and DMA revealed no significant difference (p > 0.05) between the models. The analysis showed a better adjustment of DMA using K variable, reinforced by the values of the adjustment coefficient (R2). However, convergence problems were observed in this model for estimate study areas outliers, which did not occur with K constant model. This problem can be related to the non-linear fit of mass/time values to K variable generated. The model with K constant shown to be adequate to describe curve decomposition for separately areas and best adjustability without convergence problems. The results demonstrated the adequacy of Olson model to estimate tropical forest litter decomposition. Although use of reduced number of parameters equaling the steps of the decomposition

Atlantic and indian oceans pollution in africa

Science.gov (United States)

Abubakar, Babagana

Africa is the second largest and most populated continent after Asia. Geographically it is located between the Atlantic and Indian Oceans. Most of the Africa's most populated and industrialized cities are located along the coast of the continent facing the Atlantic and Indian Oceans, example of such cities include Casablanca, Dakar, Accra, Lagos, Luanda and Cape town all facing the Atlantic Ocean and cities like East London, Durban, Maputo, Dar-es-salaam and Mogadishu are all facing the Indian Ocean. As a result of the geographical locations of African Coastal Cities plus increase in their population, industries, sea port operations, petroleum exploration activities, trafficking of toxic wastes and improper waste management culture lead to the incessant increase in the pollution of the two oceans. NATURE OF POLLUTION OF THE ATLANTIC OCEAN i. The petroleum exploration activities going on along the coast of "Gulf of Guinea" region and Angola continuously causes oil spillages in the process of drilling, bunkering and discharging of petroleum products in the Atlantic Ocean. ii. The incessant degreasing of the Sea Ports "Quay Aprons" along the Coastal cities of Lagos, Luanda, Cape Town etc are continuously polluting the Atlantic Ocean with chemicals. iii. Local wastes generated from the houses located in the coastal cities are always finding their ways into the Atlantic Ocean. NATURE OF POLLUTION OF THE INDIAN OCEAN i. Unlike the Atlantic ocean where petroleum is the major pollutant, the Indian Ocean is polluted by Toxic / Radioactive waste suspected to have been coming from the developed nations as reported by the United Nations Environmental Programme after the Tsunami disaster in December 2004 especially along the coast of Somalia. ii. The degreasing of the Quay Aprons at Port Elizabeth, Maputo, Dar-es-Salaam and Mongolism Sea Ports are also another major source polluting the Indian Ocean. PROBLEMS GENERATED AS A RESULT OF THE OCEANS POLLUTION i. Recent report

Mid-Atlantic Wind - Overcoming the Challenges

Energy Technology Data Exchange (ETDEWEB)

Daniel F. Ancona III; Kathryn E. George; Richard P. Bowers; Dr. Lynn Sparling; Bruce Buckheit; Daniel LoBue

2012-05-31

This study, supported by the US Department of Energy, Wind Powering America Program, Maryland Department of Natural Resources and Chesapeake Bay Foundation, analyzed barriers to wind energy development in the Mid-Atlantic region along with options for overcoming or mitigating them. The Mid-Atlantic States including Delaware, Maryland, North Carolina and Virginia, have excellent wind energy potential and growing demand for electricity, but only two utility-scale projects have been installed to date. Reasons for this apathetic development of wind resources were analyzed and quantified for four markets. Specific applications are: 1) Appalachian mountain ridgeline sites, 2) on coastal plains and peninsulas, 3) at shallow water sites in Delaware and Chesapeake Bays, Albemarle and Pamlico Sounds, and 4) at deeper water sites off the Atlantic coast. Each market has distinctly different opportunities and barriers. The primary barriers to wind development described in this report can be grouped into four categories; state policy and regulatory issues, wind resource technical uncertainty, economic viability, and public interest in environmental issues. The properties of these typologies are not mutually independent and do interact. The report concluded that there are no insurmountable barriers to land-based wind energy projects and they could be economically viable today. Likewise potential sites in sheltered shallow waters in regional bay and sounds have been largely overlooked but could be viable currently. Offshore ocean-based applications face higher costs and technical and wind resource uncertainties. The ongoing research and development program, revision of state incentive policies, additional wind measurement efforts, transmission system expansion, environmental baseline studies and outreach to private developers and stakeholders are needed to reduce barriers to wind energy development.

Mid-Atlantic Wind - Overcoming the Challenges

Energy Technology Data Exchange (ETDEWEB)

Daniel F. Ancona III; Kathryn E. George; Lynn Sparling; Bruce C. Buckheit; Daniel LoBue; and Richard P. Bowers

2012-06-29

This study, supported by the US Department of Energy, Wind Powering America Program, Maryland Department of Natural Resources and Chesapeake Bay Foundation, analyzed barriers to wind energy development in the Mid-Atlantic region along with options for overcoming or mitigating them. The Mid-Atlantic States including Delaware, Maryland, North Carolina and Virginia, have excellent wind energy potential and growing demand for electricity, but only two utility-scale projects have been installed to date. Reasons for this apathetic development of wind resources were analyzed and quantified for four markets. Specific applications are: 1) Appalachian mountain ridgeline sites, 2) on coastal plains and peninsulas, 3) at shallow water sites in Delaware and Chesapeake Bays, Albemarle and Pamlico Sounds, and 4) at deeper water sites off the Atlantic coast. Each market has distinctly different opportunities and barriers. The primary barriers to wind development described in this report can be grouped into four categories; state policy and regulatory issues, wind resource technical uncertainty, economic viability, and public interest in environmental issues. The properties of these typologies are not mutually independent and do interact. The report concluded that there are no insurmountable barriers to land-based wind energy projects and they could be economically viable today. Likewise potential sites in sheltered shallow waters in regional bay and sounds have been largely overlooked but could be viable currently. Offshore ocean-based applications face higher costs and technical and wind resource uncertainties. The ongoing research and development program, revision of state incentive policies, additional wind measurement efforts, transmission system expansion, environmental baseline studies and outreach to private developers and stakeholders are needed to reduce barriers to wind energy development.

Estimating tag loss of the Atlantic Horseshoe crab, Limulus polyphemus, using a multi-state model

Science.gov (United States)

Butler, Catherine Alyssa; McGowan, Conor P.; Grand, James B.; Smith, David

2012-01-01

The Atlantic Horseshoe crab, Limulus polyphemus, is a valuable resource along the Mid-Atlantic coast which has, in recent years, experienced new management paradigms due to increased concern about this species role in the environment. While current management actions are underway, many acknowledge the need for improved and updated parameter estimates to reduce the uncertainty within the management models. Specifically, updated and improved estimates of demographic parameters such as adult crab survival in the regional population of interest, Delaware Bay, could greatly enhance these models and improve management decisions. There is however, some concern that difficulties in tag resighting or complete loss of tags could be occurring. As apparent from the assumptions of a Jolly-Seber model, loss of tags can result in a biased estimate and underestimate a survival rate. Given that uncertainty, as a first step towards estimating an unbiased estimate of adult survival, we first took steps to estimate the rate of tag loss. Using data from a double tag mark-resight study conducted in Delaware Bay and Program MARK, we designed a multi-state model to allow for the estimation of mortality of each tag separately and simultaneously.

Genetic factors have a major effect on growth, number of vertebrae and otolith shape in Atlantic herring (Clupea harengus.

Directory of Open Access Journals (Sweden)

Florian Berg

Full Text Available Atlantic herring, Clupea harengus, have complex population structures. Mixing of populations is known, but the extent of connectivity is still unclear. Phenotypic plasticity results in divergent phenotypes in response to environmental factors. A marked salinity gradient occurs from Atlantic Ocean (salinity 35 into the Baltic Sea (salinity range 2-12. Herring from both habitats display phenotypic and genetic variability. To explore how genetic factors and salinity influence phenotypic traits like growth, number of vertebrae and otolith shape an experimental population consisting of Atlantic purebreds and Atlantic/Baltic F1 hybrids were incubated and co-reared at two different salinities, 16 and 35, for three years. The F1-generation was repeatedly sampled to evaluate temporal variation. A von Bertalanffy growth model indicated that reared Atlantic purebreds had a higher maximum length (26.2 cm than Atlantic/Baltic hybrids (24.8 cm at salinity 35, but not at salinity 16 (25.0 and 24.8 cm, respectively. In contrast, Atlantic/Baltic hybrids achieved larger size-at-age than the wild caught Baltic parental group. Mean vertebral counts and otolith aspect ratios were higher for reared Atlantic purebreds than Atlantic/Baltic hybrids, consistent with the differences between parental groups. There were no significant differences in vertebral counts and otolith aspect ratios between herring with the same genotype but raised in different salinities. A Canonical Analysis of Principal Coordinates was applied to analyze the variation in wavelet coefficients that described otolith shape. The first discriminating axis identified the differences between Atlantic purebreds and Atlantic/Baltic hybrids, while the second axis represented salinity differences. Assigning otoliths based on genetic groups (Atlantic purebreds vs. Atlantic/Baltic hybrids yielded higher classification success (~90% than based on salinities (16 vs. 35; ~60%. Our results demonstrate that

Dissolution of calcium carbonate: observations and model results in the subpolar North Atlantic

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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.

The impact of resolution on the adjustment and decadal variability of the Atlantic meridional overturning circulation in a coupled climate model

Energy Technology Data Exchange (ETDEWEB)

Hodson, Daniel L.R.; Sutton, Rowan T. [University of Reading, NCAS-Climate, Department of Meteorology, Earley Gate, PO Box 243, Reading (United Kingdom)

2012-12-15

Variations in the Atlantic meridional overturning circulation (MOC) exert an important influence on climate, particularly on decadal time scales. Simulation of the MOC in coupled climate models is compromised, to a degree that is unknown, by their lack of fidelity in resolving some of the key processes involved. There is an overarching need to increase the resolution and fidelity of climate models, but also to assess how increases in resolution influence the simulation of key phenomena such as the MOC. In this study we investigate the impact of significantly increasing the (ocean and atmosphere) resolution of a coupled climate model on the simulation of MOC variability by comparing high and low resolution versions of the same model. In both versions, decadal variability of the MOC is closely linked to density anomalies that propagate from the Labrador Sea southward along the deep western boundary. We demonstrate that the MOC adjustment proceeds more rapidly in the higher resolution model due the increased speed of western boundary waves. However, the response of the Atlantic sea surface temperatures to MOC variations is relatively robust - in pattern if not in magnitude - across the two resolutions. The MOC also excites a coupled ocean-atmosphere response in the tropical Atlantic in both model versions. In the higher resolution model, but not the lower resolution model, there is evidence of a significant response in the extratropical atmosphere over the North Atlantic 6 years after a maximum in the MOC. In both models there is evidence of a weak negative feedback on deep density anomalies in the Labrador Sea, and hence on the MOC (with a time scale of approximately ten years). Our results highlight the need for further work to understand the decadal variability of the MOC and its simulation in climate models. (orig.)

Macro-economic environmental models

International Nuclear Information System (INIS)

Wier, M.

1993-01-01

In the present report, an introduction to macro-economic environmental models is given. The role of the models as a tool for policy analysis is discussed. Future applications, as well as the limitations given by the data, are brought into focus. The economic-ecological system is described. A set of guidelines for implementation of the system in a traditional economic macro-model is proposed. The characteristics of empirical national and international environmental macro-economic models so far are highlighted. Special attention is paid to main economic causalities and their consequences for the environmental policy recommendations sat by the models. (au) (41 refs.)

Role of the Convective Scheme in Modeling Initiation and Intensification of Tropical Depressions over the North Atlantic

Science.gov (United States)

Duvel, Jean Philippe; Camargo, Suzana; Sobel, Adam

2016-04-01

Modifications of the large-scale environment related to intraseasonal (MJO) and interannual (ENSO) time-scale variability or to global climate warming may have important impacts on the tropical cyclonic activity. This sensitivity of tropical cyclones (TC) on environmental changes can now be studied using General Circulation Models (GCM). Before doing sensitivity studies with a GCM, it is interesting to assess the representation of the TC activity for different configurations (resolution, parameterization) of the GCM in present climate conditions and to trace possible causes of bias in TC number, location or strength. A possible approach to do this assessment is to separate initiation and intensification processes. By using either GCM output, or meteorological analysis combined to TC observation databases, it is possible to study the condition of formation of tropical depressions vortices (TDV) at an early stage and their possible intensification into a TC (say the Tropical Storm stage). We use the LMDZ GCM to study the sensitivity of TDV characteristics to different entrainment and closure formulations of the convective scheme. The study focuses on the Tropical North Atlantic using the "zoom" capability of the LMDZ GCM. The horizontal resolution of the model is set to 0.75° over a large region of the North Atlantic and West Africa. The GCM is free to run in this region and is tied to ERA-Interim reanalysis outside that region, with intermediate relaxation times in-between. We use the Tiedtke convective scheme with entrainment and closure based on the moisture convergence, or with an entrainment based on the relative humidity of the environment, and additionally a closure based on CAPE. Each configuration is run for 10 years between 2000 and 2009 with prescribed SST. In summary, the convective entrainment based on the relative humidity in the environment deepens the TDV in LMDZ, resulting in more TDV and TC. The convective closure mitigates this tendency and

ANALYSIS OF THE APPROACH TO THE ATLANTIC FOREST IN HIGH SCHOOL BIOLOGY TEXTBOOKS

Directory of Open Access Journals (Sweden)

Nicácio Oliveira Freitas

2017-03-01

Full Text Available The textbooks are the main teaching tool for students and teachers. The analysis of these books enables point out several shortcomings in relation to the contents approach. Thus, the objective of this work was to analyze the approach to the Atlantic Forest, considered one of the most degraded environments of the world. A total of seven high school biology textbooks were analyzed, following an evaluation script with general information, biotic and abiotic factors, environmental conservation and anthropic action, which were considered as satisfactory or unsatisfactory in the textbooks evaluation. In general, the Atlantic Forest theme has been addressed by all assessed books, including specific topics, however, some aspects such as the use of images was made improperly, leading to misunderstandings about Atlantic forest. In addition, ecosystem dynamics, its components and the environmental impacts have not been addressed satisfactorily in the majority of the works assessed. In general, the theme Atlantic Forest has been addressed by all assessed books, including specific topics, however, many aspects of this theme presented problems in their approach: update, concepts, definitions and importance, and also presented problems in their illustration of the current situation of Atlantic Forest. Periodic revisions of these textbooks are of great importance to assure student formation that allows them to analyze and know the effects of their actions on the environment and to reflect on ways to alleviates them. Keywords: biology textbooks; ecosystem; contents analysis.

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

77 FR 64318 - Atlantic Highly Migratory Species; Advisory Panel

Science.gov (United States)

2012-10-19

... Fishery Management Plans (FMPs) or FMP amendments for Atlantic tunas, swordfish, sharks, and billfish... membership in the HMS AP (note that there are no Environmental/NGO terms expiring, so no nominations for that...: Jenni Wallace, Highly Migratory Species Management Division, NMFS, 1315 East-West Highway, Silver Spring...

Fast northward energy transfer in the Atlantic due to Agulhas Rings

NARCIS (Netherlands)

van Sebille, Erik; van Leeuwen, P.J.

2007-01-01

The adiabatic transit time of wave energy radiated by an Agulhas ring released in the South Atlantic Ocean to the North Atlantic Ocean is investigated in a two-layer ocean model. Of particular interest is the arrival time of baroclinic energy in the northern part of the Atlantic, because it is

South Atlantic Ocean circulation: Simulation experiments with a quasi-geostrophic model and assimilation of TOPEX/POSEIDON and ERS 1 altimeter data

Science.gov (United States)

Florenchie, P.; Verron, J.

1998-10-01

Simulation experiments of South Atlantic Ocean circulations are conducted with a 1/6°, four-layered, quasi-geostrophic model. By means of a simple nudging data assimilation procedure along satellite tracks, TOPEX/POSEIDON and ERS 1 altimeter measurements are introduced into the model to control the simulation of the basin-scale circulation for the period from October 1992 to September 1994. The model circulation appears to be strongly influenced by the introduction of altimeter data, offering a consistent picture of South Atlantic Ocean circulations. Comparisons with observations show that the assimilating model successfully simulates the kinematic behavior of a large number of surface circulation components. The assimilation procedure enables us to produce schematic diagrams of South Atlantic circulation in which patterns ranging from basin-scale currents to mesoscale eddies are portrayed in a realistic way, with respect to their complexity. The major features of the South Atlantic circulation are described and analyzed, with special emphasis on the Brazil-Malvinas Confluence region, the Subtropical Gyre with the formation of frontal structures, and the Agulhas Retroflection. The Agulhas eddy-shedding process has been studied extensively. Fourteen eddies appear to be shed during the 2-year experiment. Because of their strong surface topographic signature, Agulhas eddies have been tracked continuously during the assimilation experiment as they cross the South Atlantic basin westward. Other effects of the assimilation procedure are shown, such as the intensification of the Subtropical Gyre, the appearance of a strong seasonal cycle in the Brazil Current transport, and the increase of the mean Brazil Current transport. This last result, combined with the westward oriention of the Agulhas eddies' trajectories, leads to a southward transport of mean eddy kinetic energy across 30°S.

78 FR 46923 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Snapper-Grouper Fishery off the...

Science.gov (United States)

2013-08-02

... the Caribbean, Gulf of Mexico, and South Atlantic; Snapper-Grouper Fishery off the South Atlantic... following an ACL overage, could have adverse economic and social impacts on fishery participants... implementing the procedural provisions of the National Environmental Policy Act (NEPA; 40 CFR parts 1500-1508...

A coarse resolution North Atlantic ocean circulation model: an intercomparison study with a paleoceanographic example

Directory of Open Access Journals (Sweden)

Dan Seidov

Full Text Available Paleoreconstructions suggest that during the Last Glacial Maximum (LGM the North Atlantic circulation was noticeably different from its present state. However, the glacial salt conveyor belt is believed to be similar to the present-day's conveyor, albeit weaker and shallower because of an increased freshwater flux in high-latitudes. We present here the investigation of the conveyor operation based on ocean circulation modelling using two numerical models in parallel. The GFDL primitive equation model and a planetary geostrophic model are employed to address the problem of the paleocirculation modelling in cases of uncertain and sparse data comprising the glacial surface boundary conditions. The role of different simplifications that may be used in the ocean climate studies, including the role of grid resolution, bottom topography, coast-line, etc., versus glacial-interglacial changes of the ocean surface climatology is considered. The LGM reverse conveyor gyre appeared to be the most noticeable feature of the glacial-to-interglacial alteration of the ocean circulation. The reversed upper-ocean conveyor, weaker and subducting 'normal' conveyor in the intermediate depths, and the change of the deep-ocean return flow route are robust signatures of the glacial North Atlantic climate. The results are found to be 'model-independent' and fairly insensitive to all factors other than the onset of the glacial surface conditions.

A coarse resolution North Atlantic ocean circulation model: an intercomparison study with a paleoceanographic example

Directory of Open Access Journals (Sweden)

D. Seidov

1996-02-01

Full Text Available Paleoreconstructions suggest that during the Last Glacial Maximum (LGM the North Atlantic circulation was noticeably different from its present state. However, the glacial salt conveyor belt is believed to be similar to the present-day's conveyor, albeit weaker and shallower because of an increased freshwater flux in high-latitudes. We present here the investigation of the conveyor operation based on ocean circulation modelling using two numerical models in parallel. The GFDL primitive equation model and a planetary geostrophic model are employed to address the problem of the paleocirculation modelling in cases of uncertain and sparse data comprising the glacial surface boundary conditions. The role of different simplifications that may be used in the ocean climate studies, including the role of grid resolution, bottom topography, coast-line, etc., versus glacial-interglacial changes of the ocean surface climatology is considered. The LGM reverse conveyor gyre appeared to be the most noticeable feature of the glacial-to-interglacial alteration of the ocean circulation. The reversed upper-ocean conveyor, weaker and subducting 'normal' conveyor in the intermediate depths, and the change of the deep-ocean return flow route are robust signatures of the glacial North Atlantic climate. The results are found to be 'model-independent' and fairly insensitive to all factors other than the onset of the glacial surface conditions.

Modelling the chemically aged and mixed aerosols over the eastern central Atlantic Ocean – potential impacts

Directory of Open Access Journals (Sweden)

M. Astitha

2010-07-01

Full Text Available Detailed information on the chemical and physical properties of aerosols is important for assessing their role in air quality and climate. This work explores the origin and fate of continental aerosols transported over the Central Atlantic Ocean, in terms of chemical composition, number and size distribution, using chemistry-transport models, satellite data and in situ measurements. We focus on August 2005, a period with intense hurricane and tropical storm activity over the Atlantic Ocean. A mixture of anthropogenic (sulphates, nitrates, natural (desert dust, sea salt and chemically aged (sulphate and nitrate on dust aerosols is found entering the hurricane genesis region, most likely interacting with clouds in the area. Results from our modelling study suggest rather small amounts of accumulation mode desert dust, sea salt and chemically aged dust aerosols in this Atlantic Ocean region. Aerosols of smaller size (Aitken mode are more abundant in the area and in some occasions sulphates of anthropogenic origin and desert dust are of the same magnitude in terms of number concentrations. Typical aerosol number concentrations are derived for the vertical layers near shallow cloud formation regimes, indicating that the aerosol number concentration can reach several thousand particles per cubic centimetre. The vertical distribution of the aerosols shows that the desert dust particles are often transported near the top of the marine cloud layer as they enter into the region where deep convection is initiated. The anthropogenic sulphate aerosol can be transported within a thick layer and enter the cloud deck through multiple ways (from the top, the base of the cloud, and by entrainment. The sodium (sea salt related aerosol is mostly found below the cloud base. The results of this work may provide insights relevant for studies that consider aerosol influences on cloud processes and storm development in the Central Atlantic region.

Environmental parameters affecting the structure of leaf-litter frog (Amphibia: Anura communities in tropical forests: a case study from an Atlantic Rainforest area in southeastern Brazil

Directory of Open Access Journals (Sweden)

Carla C. Siqueira

2014-04-01

Full Text Available Despite a recent increase of information on leaf litter frog communities from Atlantic rainforests, few studies have analyzed the relationship between environmental parameters and community structure of these animals. We analyzed the effects of some environmental factors on a leaf litter frog community at an Atlantic Rainforest area in southeastern Brazil. Data collection lasted ten consecutive days in January 2010, at elevations ranging between 300 and 520 m above sea level. We established 50 quadrats of 5 x 5 m on the forest floor, totaling 1,250 m² of sampled area, and recorded the mean leaf-litter depth and the number of trees within the plot, as well as altitude. We found 307 individuals belonging to ten frog species within the plots. The overall density of leaf-litter frogs estimated from the plots was 24.6 ind/100m², with Euparkerella brasiliensis (Parker, 1926, Ischnocnema guentheri (Steindachner, 1864, Ischnocnema parva (Girard, 1853 and Haddadus binotatus (Spix, 1824 presenting the highest estimated densities. Among the environmental variables analyzed, only altitude influenced the parameters of anuran community. Our results indicate that the study area has a very high density of forest floor leaf litter frogs at altitudes of 300-500 m. Future estimates of litter frog density might benefit from taking the local altitudinal variation into consideration. Neglecting such variation might result in underestimated/overestimated values if they are extrapolated to the whole area.

Energy situation in the Mid-Atlantic region

Energy Technology Data Exchange (ETDEWEB)

Munson, J S; Brainard, J P

1977-08-01

This report presents a review of the energy situation in the Mid-Atlantic Region. It describes the patterns of energy production, supply and demand by state and compares these to national and regional averages. It presents a picture of existing energy and environmental interactions and a view of potential energy and environmental conflicts. A review of the major issues by energy sector is included as is a description of the existing energy actors and major energy programs for Ohio, West Virginia, Virginia, Pennsylvania, New Jersey, New York, Delaware, Maryland, Puerto Rico, Virgin Islands, and Washington, DC.

Hierarchical modelling of temperature and habitat size effects on population dynamics of North Atlantic cod

DEFF Research Database (Denmark)

Mantzouni, Irene; Sørensen, Helle; O'Hara, Robert B.

2010-01-01

and Beverton and Holt stock–recruitment (SR) models were extended by applying hierarchical methods, mixed-effects models, and Bayesian inference to incorporate the influence of these ecosystem factors on model parameters representing cod maximum reproductive rate and carrying capacity. We identified......Understanding how temperature affects cod (Gadus morhua) ecology is important for forecasting how populations will develop as climate changes in future. The effects of spawning-season temperature and habitat size on cod recruitment dynamics have been investigated across the North Atlantic. Ricker...

75 FR 57235 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures

Science.gov (United States)

2010-09-20

.... 100825390-0431-01] RIN 0648-BA17 Atlantic Highly Migratory Species; Atlantic Shark Management Measures... on potential adjustments to the regulations governing the U.S. Atlantic shark fishery to address several specific issues currently affecting management of the shark fishery and to identify specific goals...

Final Report of the Mid-Atlantic Marine Wildlife Surveys, Modeling, and Data

Energy Technology Data Exchange (ETDEWEB)

Saracino-Brown, Jocelyn [Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States); Smith, Courtney [Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States); Gilman, Patrick [Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States)

2013-07-01

The Wind Program hosted a two-day workshop on July 24-25, 2012 with scientists and regulators engaged in marine ecological survey, modeling, and database efforts pertaining to the waters of the Mid-Atlantic region. The workshop was planned by Federal agency, academic, and private partners to promote collaboration between ongoing offshore ecological survey efforts, and to promote the collaborative development of complementary predictive models and compatible databases. The meeting primarily focused on efforts to establish and predict marine mammal, seabird, and sea turtle abundance, density, and distributions extending from the shoreline to the edge of the Exclusive Economic Zone between Nantucket Sound, Massachusetts and Cape Hatteras, North Carolina.

75 FR 30483 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures; Amendment 3

Science.gov (United States)

2010-06-01

... and 635 Atlantic Highly Migratory Species; Atlantic Shark Management Measures; Amendment 3; Final Rule... and 635 [Docket No. 080519678-0217-02] RIN 0648-AW65 Atlantic Highly Migratory Species; Atlantic Shark... available to rebuild blacknose sharks and end overfishing of blacknose and shortfin mako sharks, consistent...

76 FR 67121 - Atlantic Highly Migratory Species; 2012 Atlantic Shark Commercial Fishing Season

Science.gov (United States)

2011-10-31

.... 110913585-1625-01] RIN 0648-BB36 Atlantic Highly Migratory Species; 2012 Atlantic Shark Commercial Fishing... establish opening dates and adjust quotas for the 2012 fishing season for the Atlantic commercial shark... 2011 Atlantic commercial shark fishing seasons. In addition, NMFS proposes season openings based on...

77 FR 61562 - Atlantic Highly Migratory Species; 2013 Atlantic Shark Commercial Fishing Season

Science.gov (United States)

2012-10-10

.... 120706221-2481-01] RIN 0648-XC106 Atlantic Highly Migratory Species; 2013 Atlantic Shark Commercial Fishing... establish opening dates and adjust quotas for the 2013 fishing season for the Atlantic commercial shark... the 2011 and 2012 Atlantic commercial shark fishing seasons. We propose to keep the porbeagle shark...

Use of circulation types classifications to evaluate AR4 climate models over the Euro-Atlantic region

Energy Technology Data Exchange (ETDEWEB)

Pastor, M.A.; Casado, M.J. [Agencia Estatal de Meteorologia (AEMET), Madrid (Spain)

2012-10-15

This paper presents an evaluation of the multi-model simulations for the 4th Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) in terms of their ability to simulate the ERA40 circulation types over the Euro-Atlantic region in winter season. Two classification schemes, k-means and SANDRA, have been considered to test the sensitivity of the evaluation results to the classification procedure. The assessment allows establishing different rankings attending spatial and temporal features of the circulation types. Regarding temporal characteristics, in general, all AR4 models tend to underestimate the frequency of occurrence. The best model simulating spatial characteristics is the UKMO-HadGEM1 whereas CCSM3, UKMO-HadGEM1 and CGCM3.1(T63) are the best simulating the temporal features, for both classification schemes. This result agrees with the AR4 models ranking obtained when having analysed the ability of the same AR4 models to simulate Euro-Atlantic variability modes. This study has proved the utility of applying such a synoptic climatology approach as a diagnostic tool for models' assessment. The ability of the models to properly reproduce the position of ridges and troughs and the frequency of synoptic patterns, will therefore improve our confidence in the response of models to future climate changes. (orig.)

Understanding and simulating the link between African easterly waves and Atlantic tropical cyclones using a regional climate model: the role of domain size and lateral boundary conditions

Energy Technology Data Exchange (ETDEWEB)

Caron, Louis-Philippe [MISU, Stockholm University, Stockholm (Sweden); Universite du Quebec a Montreal, CRCMD Network, Montreal, QC (Canada); Jones, Colin G. [Swedish Meterological and Hydrological Institute, Rossby Center, Norrkoeping (Sweden)

2012-07-15

Using a suite of lateral boundary conditions, we investigate the impact of domain size and boundary conditions on the Atlantic tropical cyclone and african easterly Wave activity simulated by a regional climate model. Irrespective of boundary conditions, simulations closest to observed climatology are obtained using a domain covering both the entire tropical Atlantic and northern African region. There is a clear degradation when the high-resolution model domain is diminished to cover only part of the African continent or only the tropical Atlantic. This is found to be the result of biases in the boundary data, which for the smaller domains, have a large impact on TC activity. In this series of simulations, the large-scale Atlantic atmospheric environment appears to be the primary control on simulated TC activity. Weaker wave activity is usually accompanied by a shift in cyclogenesis location, from the MDR to the subtropics. All ERA40-driven integrations manage to capture the observed interannual variability and to reproduce most of the upward trend in tropical cyclone activity observed during that period. When driven by low-resolution global climate model (GCM) integrations, the regional climate model captures interannual variability (albeit with lower correlation coefficients) only if tropical cyclones form in sufficient numbers in the main development region. However, all GCM-driven integrations fail to capture the upward trend in Atlantic tropical cyclone activity. In most integrations, variations in Atlantic tropical cyclone activity appear uncorrelated with variations in African easterly wave activity. (orig.)

Appendix E of the Final Report of the Mid-Atlantic Marine Wildlife Surveys, Modeling, and Data

Energy Technology Data Exchange (ETDEWEB)

None

2013-07-01

The Wind Program hosted a two-day workshop on July 24-25, 2012 with scientists and regulators engaged in marine ecological survey, modeling, and database efforts pertaining to the waters of the Mid-Atlantic region. This is the fifth appendix to the report, the bibliography of references.

DECISION TOOL FOR RIPARIAN ECOSYSTEM MANAGMENT IN THE MID-ATLANTIC HIGHLANDS

Science.gov (United States)

In the Canaan Valley Highlands of the Mid-Atlantic, riparian zone restoration has been identified as a critical watershed management practice not only for the ecosystem services provided but also for the potential socioeconomic growth from environmental investment and job creatio...

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.

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.

Impact of the Atlantic Warm Pool on precipitation and temperature in Florida during North Atlantic cold spells

Energy Technology Data Exchange (ETDEWEB)

Donders, Timme H. [Utrecht University, Laboratory of Palaeobotany and Palynology, Institute of Environmental Biology, Utrecht (Netherlands); TNO Geological Survey of the Netherlands, Utrecht (Netherlands); Boer, Hugo Jan de; Dekker, Stefan C. [Utrecht University, Department of Environmental Sciences, Faculty of Geosciences, P.O. Box 80115, Utrecht (Netherlands); Finsinger, Walter; Wagner-Cremer, Friederike [Utrecht University, Laboratory of Palaeobotany and Palynology, Institute of Environmental Biology, Utrecht (Netherlands); Grimm, Eric C. [Research and Collections Center, Illinois State Museum, Springfield, IL (United States); Reichart, Gert Jan [Utrecht University, Geochemistry, Department of Earth Sciences, Faculty of Geosciences, P.O. Box 80021, Utrecht (Netherlands)

2011-01-15

Recurrent phases of increased pine at Lake Tulane, Florida have previously been related to strong stadials terminated by so-called Heinrich events. The climatic significance of these pine phases has been interpreted in different ways. Using a pollen-climate inference model, we quantified the climate changes and consistently found that mean summer precipitation (P{sub JJA}) increased (0.5-0.9 mm/day) and mean November temperature increased (2.0-3.0 C) during pine phases coeval with Heinrich events and the Younger Dryas. Marine sea surface temperature records indicate that potential sources for these moisture and heat anomalies are in the Gulf of Mexico and the western tropical Atlantic. We explain this low latitude warming by an increased Loop Current facilitated by persistence of the Atlantic Warm Pool during summer. This hypothesis is supported by a climate model sensitivity analysis. A positive heat anomaly in the Gulf of Mexico and equatorial Atlantic best approximates the pollen-inferred climate reconstructions from Lake Tulane during the (stadials around) Heinrich events and the Younger Dryas. (orig.)

Seasonal variation in biomarkers in blue mussel (Mytilus edulis), Icelandic scallop (Chlamys islandica) and Atlantic cod (Gadus morhua)-Implications for environmental monitoring in the Barents Sea

Energy Technology Data Exchange (ETDEWEB)

Nahrgang, J., E-mail: jasmine.m.nahrgang@uit.no [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); Brooks, S.J. [Norwegian Institute for Water Research (NIVA), NO-0349 Oslo (Norway); Evenset, A. [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); Camus, L. [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); University Centre In Svalbard (UNIS), NO-9171 Longyearbyen (Norway); Jonsson, M.; Smith, T.J. [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); Lukina, J. [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); University of Tromso, Faculty of Biosciences, Fisheries and Economics, Department of Arctic and Marine Biosciences, NO-9037 Tromso (Norway); Frantzen, M. [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); Giarratano, E. [Centro Nacional Patagonico (CENPAT-CONICET), AR-9120 Puerto Madryn (Argentina); Renaud, P.E. [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); University Centre In Svalbard (UNIS), NO-9171 Longyearbyen (Norway)

2013-02-15

In the Barents Sea, the limited data on biological relevant indicators and their responses to various anthropogenic stressors have hindered the development of a consistent scientific basis for selecting indicator species and developing practical procedures for environmental monitoring. Accordingly, the main aim of the present study was to develop a common set of baseline values for contaminants and biomarkers in three species, and to identify their strengths and limitations in monitoring of the Barents Sea. Blue mussel (Mytilus edulis), Icelandic scallop (Chlamys islandica) and Atlantic cod (Gadus morhua) were sampled from a north Norwegian fjord in March, June, September and December 2010. Digestive glands from the bivalve species and liver from Atlantic cod were analysed for biomarkers of oxidative stress (catalase [CAT], glutathione peroxidase [GPX], glutathione-S-transferase activities [GST], lipid peroxidation as thiobarbituric reactive substances [TBARS] and total oxyradical scavenging capacity [TOSC]), biotransformation (ethoxyresorufine-O-deethylase activity [EROD]) and general stress (lysosomal membrane stability [LMS]). Concentrations of polycyclic aromatic hydrocarbons (PAHs) and metals in the bivalves and PAH metabolites in fish bile were quantified. Finally, energy reserves (total lipids, proteins and carbohydrates) and electron transport system (ETS) activity in the digestive gland of the bivalves and liver of Atlantic cod provided background information for reproductive cycle and general physiological status of the organisms. Blue mussel and Icelandic scallop showed very similar trends in biological cycle, biomarker expression and seasonality. Biomarker baselines in Atlantic cod showed weaker seasonal variability. However, important biological events may have been undetected due to the large time intervals between sampling occasions. Physiological biomarkers such as energy reserves and ETS activity were recommended as complementary parameters to the

Determination of deep water circulation in the East Atlantic Ocean by means of a box-model based evaluation of C-14 measurements and other tracer data

International Nuclear Information System (INIS)

Schlitzer, R.

1984-01-01

Radiocarbon (C-14) measurements proved to be an efficient means of determining the average, large-area deep water circulation in the Atlantic Ocean. The thesis under review explains and discusses measurements carried out in the equatorial West Atlantic and North Atlantic Ocean. The samples have been taken during mission 56 of the RS 'meteor' in spring 1981. The gas has been obtained by vacuum extraction and the measurements have been performed in proportional counter tubes, the error to be accounted for amounting to 2per mille. These measured data, together with measurements of the potential temperatures, the silicate and CO 2 concentrations, and measured data from the South-East Atlantic Ocean, have been used to calculate on the basis of a box model of the Atlantic Ocean the deep water flow from the West to the East Atlantic Ocean, the deep water circulation between the various East Atlantic basins, and the turbulent diffusion coefficients required to parameterize the deep water mixing processes. (orig./HP) [de

AtlantOS - Optimizing and Enhancing the Integrated Atlantic Ocean Observing System

Science.gov (United States)

Reitz, Anja; Visbeck, Martin; AtlantOS Consortium, the

2016-04-01

Atlantic Ocean observation is currently undertaken through loosely-coordinated, in-situ observing networks, satellite observations and data management arrangements of heterogeneous international, national and regional design to support science and a wide range of information products. Thus there is tremendous opportunity to develop the systems towards a fully integrated Atlantic Ocean Observing System consistent with the recently developed 'Framework of Ocean Observing'. The vision of AtlantOS is to improve and innovate Atlantic observing by using the Framework of Ocean Observing to obtain an international, more sustainable, more efficient, more integrated, and fit-for-purpose system. Hence, the AtlantOS initiative will have a long-lasting and sustainable contribution to the societal, economic and scientific benefit arising from this integrated approach. This will be delivered by improving the value for money, extent, completeness, quality and ease of access to Atlantic Ocean data required by industries, product supplying agencies, scientist and citizens. The overarching target of the AtlantOS initiative is to deliver an advanced framework for the development of an integrated Atlantic Ocean Observing System that goes beyond the state-of -the-art, and leaves a legacy of sustainability after the life of the project. The legacy will derive from the following aims: i) to improve international collaboration in the design, implementation and benefit sharing of ocean observing, ii) to promote engagement and innovation in all aspects of ocean observing, iii) to facilitate free and open access to ocean data and information, iv) to enable and disseminate methods of achieving quality and authority of ocean information, v) to strengthen the Global Ocean Observing System (GOOS) and to sustain observing systems that are critical for the Copernicus Marine Environment Monitoring Service and its applications and vi) to contribute to the aims of the Galway Statement on Atlantic

Environmental Modeling Center

Data.gov (United States)

Federal Laboratory Consortium — The Environmental Modeling Center provides the computational tools to perform geostatistical analysis, to model ground water and atmospheric releases for comparison...

78 FR 59878 - Atlantic Highly Migratory Species; Commercial Atlantic Aggregated Large Coastal Shark (LCS...

Science.gov (United States)

2013-09-30

... Coastal Shark (LCS), Atlantic Hammerhead Shark, Atlantic Blacknose Shark, and Atlantic Non-Blacknose Small Coastal Shark (SCS) Management Groups AGENCY: National Marine Fisheries Service (NMFS), National Oceanic... closing the commercial management groups for aggregated LCS and hammerhead sharks in the Atlantic region...

Appendix C of the Final Report of the Mid-Atlantic Marine Wildlife Surveys, Modeling, and Data

Energy Technology Data Exchange (ETDEWEB)

None

2013-07-01

The Wind Program hosted a two-day workshop on July 24-25, 2012 with scientists and regulators engaged in marine ecological survey, modeling, and database efforts pertaining to the waters of the Mid-Atlantic region. This is the third appendix to the report, the compendium of pre-workshop answers.

Ecological regime shift drives declining growth rates of sea turtles throughout the West Atlantic

Science.gov (United States)

Bjorndal, Karen A.; Bolten, Alan B.; Chaloupka, Milani; Saba, Vincent S.; Bellini, Cláudio; Marcovaldi, Maria A.G.; Santos, Armando J.B.; Bortolon, Luis Felipe Wurdig; Meylan, Anne B.; Meylan, Peter A.; Gray, Jennifer; Hardy, Robert; Brost, Beth; Bresette, Michael; Gorham, Jonathan C.; Connett, Stephen; Crouchley, Barbara Van Sciver; Dawson, Mike; Hayes, Deborah; Diez, Carlos E.; van Dam, Robert P.; Willis, Sue; Nava, Mabel; Hart, Kristen M.; Cherkiss, Michael S.; Crowder, Andrew; Pollock, Clayton; Hillis-Starr, Zandy; Muñoz Tenería, Fernando A.; Herrera-Pavón, Roberto; Labrada-Martagón, Vanessa; Lorences, Armando; Negrete-Philippe, Ana; Lamont, Margaret M.; Foley, Allen M.; Bailey, Rhonda; Carthy, Raymond R.; Scarpino, Russell; McMichael, Erin; Provancha, Jane A.; Brooks, Annabelle; Jardim, Adriana; López-Mendilaharsu, Milagros; González-Paredes, Daniel; Estrades, Andrés; Fallabrino, Alejandro; Martínez-Souza, Gustavo; Vélez-Rubio, Gabriela M.; Boulon, Ralf H.; Collazo, Jaime; Wershoven, Robert; Hernández, Vicente Guzmán; Stringell, Thomas B.; Sanghera, Amdeep; Richardson, Peter B.; Broderick, Annette C.; Phillips, Quinton; Calosso, Marta C.; Claydon, John A.B.; Metz, Tasha L.; Gordon, Amanda L.; Landry, Andre M.; Shaver, Donna J.; Blumenthal, Janice; Collyer, Lucy; Godley, Brendan J.; McGowan, Andrew; Witt, Matthew J.; Campbell, Cathi L.; Lagueux, Cynthia J.; Bethel, Thomas L.; Kenyon, Lory

2017-01-01

Somatic growth is an integrated, individual-based response to environmental conditions, especially in ectotherms. Growth dynamics of large, mobile animals are particularly useful as bio-indicators of environmental change at regional scales. We assembled growth rate data from throughout the West Atlantic for green turtles, Chelonia mydas, which are long-lived, highly migratory, primarily herbivorous mega-consumers that may migrate over hundreds to thousands of kilometers. Our dataset, the largest ever compiled for sea turtles, has 9690 growth increments from 30 sites from Bermuda to Uruguay from 1973 to 2015. Using generalized additive mixed models, we evaluated covariates that could affect growth rates; body size, diet, and year have significant effects on growth. Growth increases in early years until 1999, then declines by 26% to 2015. The temporal (year) effect is of particular interest because two carnivorous species of sea turtles – hawksbills, Eretmochelys imbricata, and loggerheads, Caretta caretta – exhibited similar significant declines in growth rates starting in 1997 in the West Atlantic, based on previous studies. These synchronous declines in productivity among three sea turtle species across a trophic spectrum provide strong evidence that an ecological regime shift (ERS) in the Atlantic is driving growth dynamics. The ERS resulted from a synergy of the 1997/1998 El Niño Southern Oscillation (ENSO) – the strongest on record – combined with an unprecedented warming rate over the last two to three decades. Further support is provided by the strong correlations between annualized mean growth rates of green turtles and both sea surface temperatures (SST) in the West Atlantic for years of declining growth rates (r = -0.94) and the Multivariate ENSO Index (MEI) for all years (r = 0.74). Granger-causality analysis also supports the latter finding. We discuss multiple stressors that could reinforce and prolong the effect of the ERS. This study

Ecological regime shift drives declining growth rates of sea turtles throughout the West Atlantic.

Science.gov (United States)

Bjorndal, Karen A; Bolten, Alan B; Chaloupka, Milani; Saba, Vincent S; Bellini, Cláudio; Marcovaldi, Maria A G; Santos, Armando J B; Bortolon, Luis Felipe Wurdig; Meylan, Anne B; Meylan, Peter A; Gray, Jennifer; Hardy, Robert; Brost, Beth; Bresette, Michael; Gorham, Jonathan C; Connett, Stephen; Crouchley, Barbara Van Sciver; Dawson, Mike; Hayes, Deborah; Diez, Carlos E; van Dam, Robert P; Willis, Sue; Nava, Mabel; Hart, Kristen M; Cherkiss, Michael S; Crowder, Andrew G; Pollock, Clayton; Hillis-Starr, Zandy; Muñoz Tenería, Fernando A; Herrera-Pavón, Roberto; Labrada-Martagón, Vanessa; Lorences, Armando; Negrete-Philippe, Ana; Lamont, Margaret M; Foley, Allen M; Bailey, Rhonda; Carthy, Raymond R; Scarpino, Russell; McMichael, Erin; Provancha, Jane A; Brooks, Annabelle; Jardim, Adriana; López-Mendilaharsu, Milagros; González-Paredes, Daniel; Estrades, Andrés; Fallabrino, Alejandro; Martínez-Souza, Gustavo; Vélez-Rubio, Gabriela M; Boulon, Ralf H; Collazo, Jaime A; Wershoven, Robert; Guzmán Hernández, Vicente; Stringell, Thomas B; Sanghera, Amdeep; Richardson, Peter B; Broderick, Annette C; Phillips, Quinton; Calosso, Marta; Claydon, John A B; Metz, Tasha L; Gordon, Amanda L; Landry, Andre M; Shaver, Donna J; Blumenthal, Janice; Collyer, Lucy; Godley, Brendan J; McGowan, Andrew; Witt, Matthew J; Campbell, Cathi L; Lagueux, Cynthia J; Bethel, Thomas L; Kenyon, Lory

2017-11-01

Somatic growth is an integrated, individual-based response to environmental conditions, especially in ectotherms. Growth dynamics of large, mobile animals are particularly useful as bio-indicators of environmental change at regional scales. We assembled growth rate data from throughout the West Atlantic for green turtles, Chelonia mydas, which are long-lived, highly migratory, primarily herbivorous mega-consumers that may migrate over hundreds to thousands of kilometers. Our dataset, the largest ever compiled for sea turtles, has 9690 growth increments from 30 sites from Bermuda to Uruguay from 1973 to 2015. Using generalized additive mixed models, we evaluated covariates that could affect growth rates; body size, diet, and year have significant effects on growth. Growth increases in early years until 1999, then declines by 26% to 2015. The temporal (year) effect is of particular interest because two carnivorous species of sea turtles-hawksbills, Eretmochelys imbricata, and loggerheads, Caretta caretta-exhibited similar significant declines in growth rates starting in 1997 in the West Atlantic, based on previous studies. These synchronous declines in productivity among three sea turtle species across a trophic spectrum provide strong evidence that an ecological regime shift (ERS) in the Atlantic is driving growth dynamics. The ERS resulted from a synergy of the 1997/1998 El Niño Southern Oscillation (ENSO)-the strongest on record-combined with an unprecedented warming rate over the last two to three decades. Further support is provided by the strong correlations between annualized mean growth rates of green turtles and both sea surface temperatures (SST) in the West Atlantic for years of declining growth rates (r = -.94) and the Multivariate ENSO Index (MEI) for all years (r = .74). Granger-causality analysis also supports the latter finding. We discuss multiple stressors that could reinforce and prolong the effect of the ERS. This study demonstrates the

Environmental model for a capital city

Directory of Open Access Journals (Sweden)

Claudia Eugenia Toca Torres

2013-06-01

Full Text Available From a review of the various options for modeling a sustainable development in its environmental dimension, this research proposes a model of environmental impact for Bogota, using the Vensim PLE software to model the pollution, the pollution load and soil contamination. The model includes a limited number of endogenous variables, as well as a greater number of exogenous variables. This modeling allows us to anticipate the environmental situation in the capital, in order to support public policies for addressing issues such as economic sanctions and moral regulations on emissions, discharges and waste, environmental measures and environmentally friendly practices

78 FR 34041 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Comprehensive Fishery Management...

Science.gov (United States)

2013-06-06

... environmental impact statement (DEIS); scoping meetings; request for comments. SUMMARY: NMFS, Southeast Region... in developing the final environmental impact statement (FEIS), and before voting to submit the FMP to... the Caribbean, Gulf of Mexico, and South Atlantic; Comprehensive Fishery Management Plan for the...

78 FR 34042 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Comprehensive Fishery Management...

Science.gov (United States)

2013-06-06

... environmental impact statement (DEIS); scoping meetings; request for comments. SUMMARY: NMFS, Southeast Region... in developing the final environmental impact statement (FEIS), and before voting to submit the FMP to... the Caribbean, Gulf of Mexico, and South Atlantic; Comprehensive Fishery Management Plan for the...

Competitive bidding for OCS leases and environmental risk

International Nuclear Information System (INIS)

Englin, J.E.; Klan, M.S.

1990-01-01

In the last few years, the role of environment has become increasingly contentious in the process of competitive bidding for exploration and development rights of offshore petroleum leases in the outer continental shelf (OCS). Although an extensive literature exists on OCS leasing per se, relatively little work focuses on the role of environmental factors. This paper examines the effect on environmental risk on the number of firms (or joint ventures) entering bids for a given tract, which relates to the effective competition for the tracts. The next section outlines a theoretical model of bidding behavior under environmental risk. The third section presents the data used to estimate the model. The fourth section gives empirical results of an analysis of Sale No. 42, conducted in 1979 for Georges Bank in the North Atlantic. The last section provides concluding remarks

Seasonal variation in biomarkers in blue mussel (Mytilus edulis), Icelandic scallop (Chlamys islandica) and Atlantic cod (Gadus morhua)—Implications for environmental monitoring in the Barents Sea

International Nuclear Information System (INIS)

Nahrgang, J.; Brooks, S.J.; Evenset, A.; Camus, L.; Jonsson, M.; Smith, T.J.; Lukina, J.; Frantzen, M.; Giarratano, E.; Renaud, P.E.

2013-01-01

In the Barents Sea, the limited data on biological relevant indicators and their responses to various anthropogenic stressors have hindered the development of a consistent scientific basis for selecting indicator species and developing practical procedures for environmental monitoring. Accordingly, the main aim of the present study was to develop a common set of baseline values for contaminants and biomarkers in three species, and to identify their strengths and limitations in monitoring of the Barents Sea. Blue mussel (Mytilus edulis), Icelandic scallop (Chlamys islandica) and Atlantic cod (Gadus morhua) were sampled from a north Norwegian fjord in March, June, September and December 2010. Digestive glands from the bivalve species and liver from Atlantic cod were analysed for biomarkers of oxidative stress (catalase [CAT], glutathione peroxidase [GPX], glutathione-S-transferase activities [GST], lipid peroxidation as thiobarbituric reactive substances [TBARS] and total oxyradical scavenging capacity [TOSC]), biotransformation (ethoxyresorufine-O-deethylase activity [EROD]) and general stress (lysosomal membrane stability [LMS]). Concentrations of polycyclic aromatic hydrocarbons (PAHs) and metals in the bivalves and PAH metabolites in fish bile were quantified. Finally, energy reserves (total lipids, proteins and carbohydrates) and electron transport system (ETS) activity in the digestive gland of the bivalves and liver of Atlantic cod provided background information for reproductive cycle and general physiological status of the organisms. Blue mussel and Icelandic scallop showed very similar trends in biological cycle, biomarker expression and seasonality. Biomarker baselines in Atlantic cod showed weaker seasonal variability. However, important biological events may have been undetected due to the large time intervals between sampling occasions. Physiological biomarkers such as energy reserves and ETS activity were recommended as complementary parameters to the

Tropical Atlantic-Korea teleconnection pattern during boreal summer season

Science.gov (United States)

Ham, Yoo-Geun; Chikamoto, Yoshimitsu; Kug, Jong-Seong; Kimoto, Masahide; Mochizuki, Takashi

2017-10-01

The remote impact of tropical Atlantic sea surface temperature (SST) variability on Korean summer precipitation is examined based on observational data analysis along with the idealized and hindcast model experiments. Observations show a significant correlation (i.e. 0.64) between Korean precipitation anomalies (averaged over 120-130°E, 35-40°N) and the tropical Atlantic SST index (averaged over 60°W-20°E, 30°S-30°N) during the June-July-August (JJA) season for the 1979-2010 period. Our observational analysis and partial-data assimilation experiments using the coupled general circulation model demonstrate that tropical Atlantic SST warming induces the equatorial low-level easterly over the western Pacific through a reorganization of the global Walker Circulation, causing a decreased precipitation over the off-equatorial western Pacific. As a Gill-type response to this diabatic forcing, an anomalous low-level anticyclonic circulation appears over the Philippine Sea, which transports wet air from the tropics to East Asia through low-level southerly, resulting an enhanced precipitation in the Korean peninsula. Multi-model hindcast experiments also show that predictive skills of Korean summer precipitation are improved by utilizing predictions of tropical Atlantic SST anomalies as a predictor for Korean precipitation anomalies.

Ocean array alters view of Atlantic conveyor

Science.gov (United States)

Kornei, Katherine

2018-02-01

Oceanographers have put a stethoscope on the coursing circulatory system of the Atlantic Ocean, and they have found a skittish pulse that's surprisingly strong in the waters east of Greenland—discoveries that should improve climate models. The powerful currents known as the Atlantic meridional overturning circulation (AMOC) are an engine in Earth's climate. The AMOC's shallower limbs—which include the Gulf Stream—move warm water from the tropics northward, warming Western Europe. In the north, the waters cool and sink, forming deeper limbs that transport the cold water back south—and sequester anthropogenic carbon in the process. Last week, at the American Geophysical Union's Ocean Sciences meeting, scientists presented the first data from an array of instruments moored in the subpolar North Atlantic, a $35 million, seven-nation project known as the Overturning in the Subpolar North Atlantic Program (OSNAP). Since 2004, researchers have gathered data from another array, at 26°N, stretching from Florida to Africa. But OSNAP is the first to monitor the circulation farther north, where a critical aspect of the overturning occurs. The observations reveal unexpected eddies and strong variability in the AMOC currents. They also show that the currents east of Greenland contribute the most to the total AMOC flow. Climate models, on the other hand, have emphasized the currents west of Greenland in the Labrador Sea.

Projected changes to South Atlantic boundary currents and confluence region in the CMIP5 models: the role of wind and deep ocean changes

Science.gov (United States)

Pontes, G. M.; Gupta, A. Sen; Taschetto, A. S.

2016-09-01

The South Atlantic (SA) circulation plays an important role in the oceanic teleconnections from the Indian, Pacific and Southern oceans to the North Atlantic, with inter-hemispheric exchanges of heat and salt. Here, we show that the large-scale features of the SA circulation are projected to change significantly under ‘business as usual’ greenhouse gas increases. Based on 19 models from the Coupled Model Intercomparison Project phase 5 there is a projected weakening in the upper ocean interior transport (stress curl over this region. The reduction in ocean interior circulation is largely compensated by a decrease in the net deep southward ocean transport (>1000 m), mainly related to a decrease in the North Atlantic deep water transport. Between 30° and 40°S, there is a consistent projected intensification in the Brazil current strength of about 40% (30%-58% interquartile range) primarily compensated by an intensification of the upper interior circulation across the Indo-Atlantic basin. The Brazil-Malvinas confluence is projected to shift southwards, driven by a weakening of the Malvinas current. Such a change could have important implications for the distribution of marine species in the southwestern SA in the future.

Southeast Atlantic Cloud Properties in a Multivariate Statistical Model - How Relevant is Air Mass History for Local Cloud Properties?

Science.gov (United States)

Fuchs, Julia; Cermak, Jan; Andersen, Hendrik

2017-04-01

This study aims at untangling the impacts of external dynamics and local conditions on cloud properties in the Southeast Atlantic (SEA) by combining satellite and reanalysis data using multivariate statistics. The understanding of clouds and their determinants at different scales is important for constraining the Earth's radiative budget, and thus prominent in climate-system research. In this study, SEA stratocumulus cloud properties are observed not only as the result of local environmental conditions but also as affected by external dynamics and spatial origins of air masses entering the study area. In order to assess to what extent cloud properties are impacted by aerosol concentration, air mass history, and meteorology, a multivariate approach is conducted using satellite observations of aerosol and cloud properties (MODIS, SEVIRI), information on aerosol species composition (MACC) and meteorological context (ERA-Interim reanalysis). To account for the often-neglected but important role of air mass origin, information on air mass history based on HYSPLIT modeling is included in the statistical model. This multivariate approach is intended to lead to a better understanding of the physical processes behind observed stratocumulus cloud properties in the SEA.

Environmental forcing of nitrogen fixation in the eastern tropical and sub-tropical North Atlantic Ocean.

Science.gov (United States)

Rijkenberg, Micha J A; Langlois, Rebecca J; Mills, Matthew M; Patey, Matthew D; Hill, Polly G; Nielsdóttir, Maria C; Compton, Tanya J; Laroche, Julie; Achterberg, Eric P

2011-01-01

During the winter of 2006 we measured nifH gene abundances, dinitrogen (N(2)) fixation rates and carbon fixation rates in the eastern tropical and sub-tropical North Atlantic Ocean. The dominant diazotrophic phylotypes were filamentous cyanobacteria, which may include Trichodesmium and Katagnymene, with up to 10(6) L(-1)nifH gene copies, unicellular group A cyanobacteria with up to 10(5) L(-1)nifH gene copies and gamma A proteobacteria with up to 10(4) L(-1)nifH gene copies. N(2) fixation rates were low and ranged between 0.032-1.28 nmol N L(-1) d(-1) with a mean of 0.30 ± 0.29 nmol N L(-1) d(-1) (1σ, n = 65). CO(2)-fixation rates, representing primary production, appeared to be nitrogen limited as suggested by low dissolved inorganic nitrogen to phosphate ratios (DIN:DIP) of about 2 ± 3.2 in surface waters. Nevertheless, N(2) fixation rates contributed only 0.55 ± 0.87% (range 0.03-5.24%) of the N required for primary production. Boosted regression trees analysis (BRT) showed that the distribution of the gamma A proteobacteria and filamentous cyanobacteria nifH genes was mainly predicted by the distribution of Prochlorococcus, Synechococcus, picoeukaryotes and heterotrophic bacteria. In addition, BRT indicated that multiple a-biotic environmental variables including nutrients DIN, dissolved organic nitrogen (DON) and DIP, trace metals like dissolved aluminum (DAl), as a proxy of dust inputs, dissolved iron (DFe) and Fe-binding ligands as well as oxygen and temperature influenced N(2) fixation rates and the distribution of the dominant diazotrophic phylotypes. Our results suggest that lower predicted oxygen concentrations and higher temperatures due to climate warming may increase N(2) fixation rates. However, the balance between a decreased supply of DIP and DFe from deep waters as a result of more pronounced stratification and an enhanced supply of these nutrients with a predicted increase in deposition of Saharan dust may ultimately determine the

Genetic heterogeneity of within-family variance of body weight in Atlantic salmon (Salmo salar).

Science.gov (United States)

Sonesson, Anna K; Odegård, Jørgen; Rönnegård, Lars

2013-10-17

Canalization is defined as the stability of a genotype against minor variations in both environment and genetics. Genetic variation in degree of canalization causes heterogeneity of within-family variance. The aims of this study are twofold: (1) quantify genetic heterogeneity of (within-family) residual variance in Atlantic salmon and (2) test whether the observed heterogeneity of (within-family) residual variance can be explained by simple scaling effects. Analysis of body weight in Atlantic salmon using a double hierarchical generalized linear model (DHGLM) revealed substantial heterogeneity of within-family variance. The 95% prediction interval for within-family variance ranged from ~0.4 to 1.2 kg2, implying that the within-family variance of the most extreme high families is expected to be approximately three times larger than the extreme low families. For cross-sectional data, DHGLM with an animal mean sub-model resulted in severe bias, while a corresponding sire-dam model was appropriate. Heterogeneity of variance was not sensitive to Box-Cox transformations of phenotypes, which implies that heterogeneity of variance exists beyond what would be expected from simple scaling effects. Substantial heterogeneity of within-family variance was found for body weight in Atlantic salmon. A tendency towards higher variance with higher means (scaling effects) was observed, but heterogeneity of within-family variance existed beyond what could be explained by simple scaling effects. For cross-sectional data, using the animal mean sub-model in the DHGLM resulted in biased estimates of variance components, which differed substantially both from a standard linear mean animal model and a sire-dam DHGLM model. Although genetic differences in canalization were observed, selection for increased canalization is difficult, because there is limited individual information for the variance sub-model, especially when based on cross-sectional data. Furthermore, potential macro-environmental

Water environments: anthropogenic pressures and ecosystem changes in the Atlantic drainage basins of Brazil.

Science.gov (United States)

Marques, Marcia; da Costa, Monica F; Mayorga, Maria Irles de O; Pinheiro, Patrícia R

2004-02-01

Densely occupied drainage basins and coastal zones in developing countries that are facing economic growth are likely to suffer from moderate to severe environmental impacts regarding different issues. The catchment basins draining towards the Atlantic coast from northeastern to southern Brazil include a wide range of climatic zones and diverse ecosystems. Within its borders lies the Atlantic rain forest, significant extensions of semiarid thorn forests (caatinga), vast tree and scrub woodlands (cerrado) and most of the 6670 km of the Brazilian coast and its marine ecosystems. In recent decades, human activities have increasingly advanced over these natural resources. Littoralization has imposed a burden on coastal habitats and communities. Most of the native vegetation of the cerrado and caatinga was removed and only 7% of the original Atlantic rainforest still exists. Estuaries, bays and coastal lagoons have been irreversibly damaged. Land uses, damming and water diversion have become the major driving forces for habitat loss and aquatic ecosystem modification. Regardless of the contrast between the drought-affected northeastern Brazil and the much more prosperous and industrialized southeastern/southern Brazil, the impacts on habitat and communities were found equally severe in both cases. Attempts to halt environmental degradation have not been effective. Instead of focusing on natural resources separately, it is suggested that more integrated environmental policies that focus on aquatic ecosystems integrity are introduced.

78 FR 52487 - Atlantic Highly Migratory Species; 2014 Atlantic Shark Commercial Fishing Season

Science.gov (United States)

2013-08-23

.... 130402317-3707-01] RIN 0648-XC611 Atlantic Highly Migratory Species; 2014 Atlantic Shark Commercial Fishing... establish opening dates and adjust quotas for the 2014 fishing season for the Atlantic commercial shark... management measures to provide, to the extent practicable, fishing opportunities for commercial shark...

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

Global Warming Attenuates the Tropical Atlantic-Pacific Teleconnection

Science.gov (United States)

Jia, Fan; Wu, Lixin; Gan, Bolan; Cai, Wenju

2016-01-01

Changes in global sea surface temperature (SST) since the end of last century display a pattern of widespread warming intercepted by cooling in the eastern equatorial Pacific and western coasts of the American continent. Studies have suggested that the cooling in the eastern equatorial Pacific may be partly induced by warming in the North Atlantic. However, it remains unknown how stable this inter-tropical teleconnection will be under global warming. Here we show that the inter-tropical teleconnection from the tropical Atlantic to Pacific weakens substantially as the CO2 concentration increases. This reduced impact is related to the El Niño-like warming of the tropical Pacific mean state, which leads to limited seasonal migration of the Pacific inter-tropical convergence zone (ITCZ) and weakened ocean heat transport. A fast decay of the tropical Atlantic SST anomalies in a warmer climate also contributes to the weakened teleconnection. Our study suggests that as greenhouse warming continues, the trend in the tropical Pacific as well as the development of ENSO will be less frequently interrupted by the Atlantic because of this attenuation. The weakened teleconnection is also supported by CMIP5 models, although only a few of these models can capture this inter-tropical teleconnection. PMID:26838053

Global Warming Attenuates the Tropical Atlantic-Pacific Teleconnection.

Science.gov (United States)

Jia, Fan; Wu, Lixin; Gan, Bolan; Cai, Wenju

2016-02-03

Changes in global sea surface temperature (SST) since the end of last century display a pattern of widespread warming intercepted by cooling in the eastern equatorial Pacific and western coasts of the American continent. Studies have suggested that the cooling in the eastern equatorial Pacific may be partly induced by warming in the North Atlantic. However, it remains unknown how stable this inter-tropical teleconnection will be under global warming. Here we show that the inter-tropical teleconnection from the tropical Atlantic to Pacific weakens substantially as the CO2 concentration increases. This reduced impact is related to the El Niño-like warming of the tropical Pacific mean state, which leads to limited seasonal migration of the Pacific inter-tropical convergence zone (ITCZ) and weakened ocean heat transport. A fast decay of the tropical Atlantic SST anomalies in a warmer climate also contributes to the weakened teleconnection. Our study suggests that as greenhouse warming continues, the trend in the tropical Pacific as well as the development of ENSO will be less frequently interrupted by the Atlantic because of this attenuation. The weakened teleconnection is also supported by CMIP5 models, although only a few of these models can capture this inter-tropical teleconnection.

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)

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)

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)

Modeling the potential spread of the recently identified non-native panther grouper (Chromileptes altivelis) in the Atlantic using a cellular automaton approach.

Science.gov (United States)

Johnston, Matthew W; Purkis, Sam J

2013-01-01

The Indo-pacific panther grouper (Chromileptes altiveli) is a predatory fish species and popular imported aquarium fish in the United States which has been recently documented residing in western Atlantic waters. To date, the most successful marine invasive species in the Atlantic is the lionfish (Pterois volitans/miles), which, as for the panther grouper, is assumed to have been introduced to the wild through aquarium releases. However, unlike lionfish, the panther grouper is not yet thought to have an established breeding population in the Atlantic. Using a proven modeling technique developed to track the lionfish invasion, presented is the first known estimation of the potential spread of panther grouper in the Atlantic. The employed cellular automaton-based computer model examines the life history of the subject species including fecundity, mortality, and reproductive potential and combines this with habitat preferences and physical oceanic parameters to forecast the distribution and periodicity of spread of this potential new invasive species. Simulations were examined for origination points within one degree of capture locations of panther grouper from the United States Geological Survey Nonindigenous Aquatic Species Database to eliminate introduction location bias, and two detailed case studies were scrutinized. The model indicates three primary locations where settlement is likely given the inputs and limits of the model; Jupiter Florida/Vero Beach, the Cape Hatteras Tropical Limit/Myrtle Beach South Carolina, and Florida Keys/Ten Thousand Islands locations. Of these locations, Jupiter Florida/Vero Beach has the highest settlement rate in the model and is indicated as the area in which the panther grouper is most likely to become established. This insight is valuable if attempts are to be made to halt this potential marine invasive species.

Modeling the potential spread of the recently identified non-native panther grouper (Chromileptes altivelis in the Atlantic using a cellular automaton approach.

Directory of Open Access Journals (Sweden)

Matthew W Johnston

Full Text Available The Indo-pacific panther grouper (Chromileptes altiveli is a predatory fish species and popular imported aquarium fish in the United States which has been recently documented residing in western Atlantic waters. To date, the most successful marine invasive species in the Atlantic is the lionfish (Pterois volitans/miles, which, as for the panther grouper, is assumed to have been introduced to the wild through aquarium releases. However, unlike lionfish, the panther grouper is not yet thought to have an established breeding population in the Atlantic. Using a proven modeling technique developed to track the lionfish invasion, presented is the first known estimation of the potential spread of panther grouper in the Atlantic. The employed cellular automaton-based computer model examines the life history of the subject species including fecundity, mortality, and reproductive potential and combines this with habitat preferences and physical oceanic parameters to forecast the distribution and periodicity of spread of this potential new invasive species. Simulations were examined for origination points within one degree of capture locations of panther grouper from the United States Geological Survey Nonindigenous Aquatic Species Database to eliminate introduction location bias, and two detailed case studies were scrutinized. The model indicates three primary locations where settlement is likely given the inputs and limits of the model; Jupiter Florida/Vero Beach, the Cape Hatteras Tropical Limit/Myrtle Beach South Carolina, and Florida Keys/Ten Thousand Islands locations. Of these locations, Jupiter Florida/Vero Beach has the highest settlement rate in the model and is indicated as the area in which the panther grouper is most likely to become established. This insight is valuable if attempts are to be made to halt this potential marine invasive species.

Freight planning and regional cooperation in the Piedmont Atlantic megaregion : a regional models of cooperation peer exchange summary report

Science.gov (United States)

2017-09-08

This report highlights key themes identified at the Freight Planning and Regional Cooperation in the Piedmont Atlantic Megaregion Peer Exchange held on January 31, 2017 and February 1, 2017 in Atlanta, Georgia. The Regional Models of Cooperatio...

Spatial heterogeneity and the distribution of bromeliad pollinators in the Atlantic Forest

Science.gov (United States)

Varassin, Isabela Galarda; Sazima, Marlies

2012-08-01

Interactions between plants and their pollinators are influenced by environmental heterogeneity, resulting in small-scale variations in interactions. This may influence pollinator co-existence and plant reproductive success. This study, conducted at the Estação Biológica de Santa Lúcia (EBSL), a remnant of the Atlantic Forest in southeastern Brazil, investigated the effect of small-scale spatial variations on the interactions between bromeliads and their pollinators. Overall, hummingbirds pollinated 19 of 23 bromeliad species, of which 11 were also pollinated by bees and/or butterflies. However, spatial heterogeneity unrelated to the spatial location of plots or bromeliad species abundance influenced the presence of pollinators. Hummingbirds were the most ubiquitous pollinators at the high-elevation transect, with insect participation clearly declining as transect elevation increased. In the redundancy analysis, the presence of the hummingbird species Phaethornis eurynome, Phaethornis squalidus, Ramphodon naevius, and Thalurania glaucopis, and the butterfly species Heliconius erato and Heliconius nattereri in each plot was correlated with environmental factors such as bromeliad and tree abundance, and was also correlated with horizontal diversity. Since plant-pollinator interactions varied within the environmental mosaics at the study site, this small-scale environmental heterogeneity may relax competition among pollinators, and may explain the high diversity of bromeliads and pollinators generally found in the Atlantic Forest.

Atlantic Canada's energy research and development website and database

International Nuclear Information System (INIS)

2005-01-01

Petroleum Research Atlantic Canada maintains a website devoted to energy research and development in Atlantic Canada. The site can be viewed on the world wide web at www.energyresearch.ca. It includes a searchable database with information about researchers in Nova Scotia, their projects and published materials on issues related to hydrocarbons, alternative energy technologies, energy efficiency, climate change, environmental impacts and policy. The website also includes links to research funding agencies, external related databases and related energy organizations around the world. Nova Scotia-based users are invited to submit their academic, private or public research to the site. Before being uploaded into the database, a site administrator reviews and processes all new information. Users are asked to identify their areas of interest according to the following research categories: alternative or renewable energy technologies; climate change; coal; computer applications; economics; energy efficiency; environmental impacts; geology; geomatics; geophysics; health and safety; human factors; hydrocarbons; meteorology and oceanology (metocean) activities; petroleum operations in deep and shallow waters; policy; and power generation and supply. The database can be searched 5 ways according to topic, researchers, publication, projects or funding agency. refs., tabs., figs

Simulation of the 1979 spring bloom in the Mid-Atlantic Bight - A coupled physical/biological/optical model

Science.gov (United States)

Gregg, Watson W.; Walsh, John J.

1992-01-01

A coupled physical/biological/optical model is developed for studies of phytoplankton variability in the spring 1979 Mid-Atlantic Bight, as observed by CZCS imagery. The model incorporates advection, mixing, sinking, growth as a function of light, temperature, nutrient availability, and death as a function of ingestion. It produced chlorophyll concentrations within the first attenuated depth within 1 standard deviation of CZCS imagery on large scale. The primary production estimates obtained using this model were within reasonable agreement with those measured in situ.

75 FR 44938 - Atlantic Coastal Fisheries Cooperative Management Act Provisions; Atlantic Coastal Shark Fishery

Science.gov (United States)

2010-07-30

... Coastal Fisheries Cooperative Management Act Provisions; Atlantic Coastal Shark Fishery AGENCY: National... moratorium on fishing for Atlantic coastal sharks in the State waters of New Jersey. NMFS canceled the... Fisheries Commission's (Commission) Interstate Fishery Management Plan for Atlantic Coastal Sharks (Coastal...

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.

Characterising performance of environmental models

NARCIS (Netherlands)

Bennett, N.D.; Croke, B.F.W.; Guariso, G.; Guillaume, J.H.A.; Hamilton, S.H.; Jakeman, A.J.; Marsili-Libelli, S.; Newham, L.T.H.; Norton, J.; Perrin, C.; Pierce, S.; Robson, B.; Seppelt, R.; Voinov, A.; Fath, B.D.; Andreassian, V.

2013-01-01

In order to use environmental models effectively for management and decision-making, it is vital to establish an appropriate level of confidence in their performance. This paper reviews techniques available across various fields for characterising the performance of environmental models with focus

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.

Pathways of fish invasions in the Mid-Atlantic region of the United States

Science.gov (United States)

Lapointe, Nicolas W. R.; Fuller, Pam; Neilson, Matthew; Murphy, Brian R.; Angermeier, Paul

2016-01-01

Non-native fish introductions are a major threat to biodiversity and fisheries, and occur through numerous pathways that vary regionally in importance. A key strategy for managing invasions is to focus prevention efforts on pathways posing the greatest risk of future introductions. We identified high-risk pathways for fish establishment in the Mid-Atlantic region of the United States based on estimates of probability of establishment and records of previous introductions, which were considered in the context of emerging socioeconomic trends. We used estimates of propagule pressure, species’ environmental tolerance, and size of species pool to assess the risk of establishment by pathway. Pathways varied considerably in historic importance and species composition, with the majority of species introduced intentionally via stocking (primarily for sport, forage, or biocontrol) or bait release. Bait release, private stocking, illegal introductions intended to establish reproducing populations (e.g., of sport fish), aquaculture, and the sale of live organisms all create risks for future invasions in the Mid-Atlantic region. Of these pathways, bait release probably poses the greatest risk of introductions for the Mid-Atlantic region because propagule pressure is moderate, most released species are tolerant of local environmental conditions, and the pool of species available for transplantation is large. Our findings differ considerably from studies in other regions (e.g., bait release is a dominant pathway in the Mid-Atlantic region, whereas illegal introduction of sport fish is dominant in the western US and aquarium releases are dominant in Florida), demonstrating the need for regional-scale assessments of, and management strategies for, introduction pathways.

Landslide monitoring in the Atlantic Highlands area, New Jersey

Science.gov (United States)

Reilly, Pamela A.; Ashland, Francis X.; Fiore, Alex R.

2017-08-25

Shallow and deep-seated landslides have occurred episodically on the steep coastal bluffs of the Atlantic Highlands area (Boroughs of Atlantic Highlands and Highlands) in New Jersey. The oldest documented deep-seated landslide occurred in April 1782 and significantly changed the morphology of the bluff. However, recent landslides have been mostly shallow in nature and have occurred during large storms with exceptionally heavy rainfall. These shallow landslides have resulted in considerable damage to residential property and local infrastructure and threatened human safety.The recent shallow landslides in the area (locations modified from New Jersey Department of Environmental Protection) consist primarily of slumps and flows of earth and debris within areas of historical landslides or on slopes modified by human activities. Such landslides are typically triggered by increases in shallow soil moisture and pore-water pressure caused by sustained and intense rainfall associated with spring nor’easters and late summer–fall tropical cyclones. However, the critical relation between rainfall, soil-moisture conditions, and landslide movement has not been fully defined. The U.S. Geological Survey is currently monitoring hillslopes within the Atlantic Highlands area to better understand the hydrologic and meteorological conditions associated with shallow landslide initiation.

A regional ocean circulation model for the mid-Cretaceous North Atlantic Basin: implications for black shale formation

Directory of Open Access Journals (Sweden)

R. P. M. Topper

2011-03-01

Full Text Available High concentrations of organic matter accumulated in marine sediments during Oceanic Anoxic Events (OAEs in the Cretaceous. Model studies examining these events invariably make use of global ocean circulation models. In this study, a regional model for the North Atlantic Basin during OAE2 at the Cenomanian-Turonian boundary has been developed. A first order check of the results has been performed by comparison with the results of a recent global Cenomanian CCSM3 run, from which boundary and initial conditions were obtained. The regional model is able to maintain tracer patterns and to produce velocity patterns similar to the global model. The sensitivity of the basin tracer and circulation patterns to changes in the geometry of the connections with the global ocean is examined with three experiments with different bathymetries near the sponges. Different geometries turn out to have little effect on tracer distribution, but do affect circulation and upwelling patterns. The regional model is also used to test the hypothesis that ocean circulation may have been behind the deposition of black shales during OAEs. Three scenarios are tested which are thought to represent pre-OAE, OAE and post-OAE situations. Model results confirm that Pacific intermediate inflow together with coastal upwelling could have enhanced primary production during OAE2. A low sea level in the pre-OAE scenario could have inhibited large scale black shale formation, as could have the opening of the Equatorial Atlantic Seaway in the post-OAE scenario.

Modeling ozone plumes observed downwind of New York City over the North Atlantic Ocean during the ICARTT field campaign

Directory of Open Access Journals (Sweden)

S.-H. Lee

2011-07-01

Full Text Available Transport and chemical transformation of well-defined New York City (NYC urban plumes over the North Atlantic Ocean were studied using aircraft measurements collected on 20–21 July 2004 during the ICARTT (International Consortium for Atmospheric Research on Transport and Transformation field campaign and WRF-Chem (Weather Research and Forecasting-Chemistry model simulations. The strong NYC urban plumes were characterized by carbon monoxide (CO mixing ratios of 350–400 parts per billion by volume (ppbv and ozone (O₃ levels of about 100 ppbv near New York City on 20 July in the WP-3D in-situ and DC-3 lidar aircraft measurements. On 21 July, the two aircraft captured strong urban plumes with about 350 ppbv CO and over 150 ppbv O₃ (~160 ppbv maximum about 600 km downwind of NYC over the North Atlantic Ocean. The measured urban plumes extended vertically up to about 2 km near New York City, but shrank to 1–1.5 km over the stable marine boundary layer (MBL over the North Atlantic Ocean. The WRF-Chem model reproduced ozone formation processes, chemical characteristics, and meteorology of the measured urban plumes near New York City (20 July and in the far downwind region over the North Atlantic Ocean (21 July. The quasi-Lagrangian analysis of transport and chemical transformation of the simulated NYC urban plumes using WRF-Chem results showed that the pollutants can be efficiently transported in (isentropic layers in the lower atmosphere (<2–3 km over the North Atlantic Ocean while maintaining a dynamic vertical decoupling by cessation of turbulence in the stable MBL. The O₃ mixing ratio in the NYC urban plumes remained at 80–90 ppbv during nocturnal transport over the stable MBL, then grew to over 100 ppbv by daytime oxidation of nitrogen oxides (NO_x = NO + NO₂ with mixing ratios on the order of 1 ppbv. Efficient transport of reactive nitrogen species (NO_y, specifically nitric

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...

Lithospheric thickness jumps at the S-Atlantic continental margins from satellite gravity data and modelled isostatic anomalies

Science.gov (United States)

Shahraki, Meysam; Schmeling, Harro; Haas, Peter

2018-01-01

Isostatic equilibrium is a good approximation for passive continental margins. In these regions, geoid anomalies are proportional to the local dipole moment of density-depth distributions, which can be used to constrain the amount of oceanic to continental lithospheric thickening (lithospheric jumps). We consider a five- or three-layer 1D model for the oceanic and continental lithosphere, respectively, composed of water, a sediment layer (both for the oceanic case), the crust, the mantle lithosphere and the asthenosphere. The mantle lithosphere is defined by a mantle density, which is a function of temperature and composition, due to melt depletion. In addition, a depth-dependent sediment density associated with compaction and ocean floor variation is adopted. We analyzed satellite derived geoid data and, after filtering, extracted typical averaged profiles across the Western and Eastern passive margins of the South Atlantic. They show geoid jumps of 8.1 m and 7.0 m for the Argentinian and African sides, respectively. Together with topography data and an averaged crustal density at the conjugate margins these jumps are interpreted as isostatic geoid anomalies and yield best-fitting crustal and lithospheric thicknesses. In a grid search approach five parameters are systematically varied, namely the thicknesses of the sediment layer, the oceanic and continental crusts and the oceanic and the continental mantle lithosphere. The set of successful models reveals a clear asymmetry between the South Africa and Argentine lithospheres by 15 km. Preferred models predict a sediment layer at the Argentine margin of 3-6 km and at the South Africa margin of 1-2.5 km. Moreover, we derived a linear relationship between, oceanic lithosphere, sediment thickness and lithospheric jumps at the South Atlantic margins. It suggests that the continental lithospheres on the western and eastern South Atlantic are thicker by 45-70 and 60-80 km than the oceanic lithospheres, respectively.

Footprints of directional selection in wild Atlantic salmon populations: evidence for parasite-driven evolution?

Science.gov (United States)

Zueva, Ksenia J; Lumme, Jaakko; Veselov, Alexey E; Kent, Matthew P; Lien, Sigbjørn; Primmer, Craig R

2014-01-01

Mechanisms of host-parasite co-adaptation have long been of interest in evolutionary biology; however, determining the genetic basis of parasite resistance has been challenging. Current advances in genome technologies provide new opportunities for obtaining a genome-scale view of the action of parasite-driven natural selection in wild populations and thus facilitate the search for specific genomic regions underlying inter-population differences in pathogen response. European populations of Atlantic salmon (Salmo salar L.) exhibit natural variance in susceptibility levels to the ectoparasite Gyrodactylus salaris Malmberg 1957, ranging from resistance to extreme susceptibility, and are therefore a good model for studying the evolution of virulence and resistance. However, distinguishing the molecular signatures of genetic drift and environment-associated selection in small populations such as land-locked Atlantic salmon populations presents a challenge, specifically in the search for pathogen-driven selection. We used a novel genome-scan analysis approach that enabled us to i) identify signals of selection in salmon populations affected by varying levels of genetic drift and ii) separate potentially selected loci into the categories of pathogen (G. salaris)-driven selection and selection acting upon other environmental characteristics. A total of 4631 single nucleotide polymorphisms (SNPs) were screened in Atlantic salmon from 12 different northern European populations. We identified three genomic regions potentially affected by parasite-driven selection, as well as three regions presumably affected by salinity-driven directional selection. Functional annotation of candidate SNPs is consistent with the role of the detected genomic regions in immune defence and, implicitly, in osmoregulation. These results provide new insights into the genetic basis of pathogen susceptibility in Atlantic salmon and will enable future searches for the specific genes involved.

75 FR 33531 - Atlantic Highly Migratory Species; Atlantic Bluefin Tuna Fisheries

Science.gov (United States)

2010-06-14

... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 635 RIN 0648-XW79 Atlantic Highly Migratory Species; Atlantic Bluefin Tuna Fisheries AGENCY: National Marine..., recent Large Pelagics Survey estimates indicate that charter/headboat BFT landings constitute...

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

Interaction between Tropical Atlantic Variability and El Niño-Southern Oscillation.

Science.gov (United States)

Saravanan, R.; Chang, Ping

2000-07-01

The interaction between tropical Atlantic variability and El Niño-Southern Oscillation (ENSO) is investigated using three ensembles of atmospheric general circulation model integrations. The integrations are forced by specifying observed sea surface temperature (SST) variability over a forcing domain. The forcing domain is the global ocean for the first ensemble, limited to the tropical ocean for the second ensemble, and further limited to the tropical Atlantic region for the third ensemble. The ensemble integrations show that extratropical SST anomalies have little impact on tropical variability, but the effect of ENSO is pervasive in the Tropics. Consistent with previous studies, the most significant influence of ENSO is found during the boreal spring season and is associated with an anomalous Walker circulation. Two important aspects of ENSO's influence on tropical Atlantic variability are noted. First, the ENSO signal contributes significantly to the `dipole' correlation structure between tropical Atlantic SST and rainfall in the Nordeste Brazil region. In the absence of the ENSO signal, the correlations are dominated by SST variability in the southern tropical Atlantic, resulting in less of a dipole structure. Second, the remote influence of ENSO also contributes to positive correlations between SST anomalies and downward surface heat flux in the tropical Atlantic during the boreal spring season. However, even when ENSO forcing is absent, the model integrations provide evidence for a positive surface heat flux feedback in the deep Tropics, which is analyzed in a companion study by Chang et al. The analysis of model simulations shows that interannual atmospheric variability in the tropical Pacific-Atlantic system is dominated by the interaction between two distinct sources of tropical heating: (i) an equatorial heat source in the eastern Pacific associated with ENSO and (ii) an off-equatorial heat source associated with SST anomalies near the Caribbean

Modelled spatial and seasonal distribution of Blue Whiting (Micromesistius poutassou) larvae in the North-East Atlantic (1951 to 2005)

DEFF Research Database (Denmark)

2014-01-01

Blue whiting (Micromesistius poutassou, http://www.marinespecies.org/aphia.php?p=taxdetails&id=126439) is a small mesopelagic planktivorous gadoid found throughout the North-East Atlantic. This data contains the results of a model-based analysis of larvae captured by the Continuous Plankton...

Modeling Environmental Literacy of University Students

Science.gov (United States)

Teksoz, Gaye; Sahin, Elvan; Tekkaya-Oztekin, Ceren

2012-01-01

The present study proposed an Environmental Literacy Components Model to explain how environmental attitudes, environmental responsibility, environmental concern, and environmental knowledge as well as outdoor activities related to each other. A total of 1,345 university students responded to an environmental literacy survey (Kaplowitz and Levine…

Optimal flight altitude and flight routes with respect to environmental and economical aspects

Energy Technology Data Exchange (ETDEWEB)

Nodorp, D.; Sausen, R.; Land, C. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere; Deidewig, F. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Koeln (Germany). Inst. fuer Antriebstechnik

1997-12-31

A flight routing method is presented. In addition to conventional minimization of travel time and/or fuel consumption it also takes into account the environmental impact of the aircraft emissions on the climate system. In the process the ECHAM general circulation model is used to trace the pollutants after release, estimate their potential to cause damage and to weight this environmental relative to the economical aspect. Some case studies are presented for an Airbus A340 in the North Atlantic flight corridor. (author) 6 refs.

Optimal flight altitude and flight routes with respect to environmental and economical aspects

Energy Technology Data Exchange (ETDEWEB)

Nodorp, D; Sausen, R; Land, C [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere; Deidewig, F [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Koeln (Germany). Inst. fuer Antriebstechnik

1998-12-31

A flight routing method is presented. In addition to conventional minimization of travel time and/or fuel consumption it also takes into account the environmental impact of the aircraft emissions on the climate system. In the process the ECHAM general circulation model is used to trace the pollutants after release, estimate their potential to cause damage and to weight this environmental relative to the economical aspect. Some case studies are presented for an Airbus A340 in the North Atlantic flight corridor. (author) 6 refs.

76 FR 23935 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures

Science.gov (United States)

2011-04-29

.... 110120049-1144-01] RIN 0648-BA69 Atlantic Highly Migratory Species; Atlantic Shark Management Measures... retention, transshipping, landing, storing, or selling of hammerhead sharks in the family Sphyrnidae (except for Sphyrna tiburo) and oceanic whitetip sharks (Carcharhinus longimanus) caught in association with...

76 FR 65700 - Atlantic Highly Migratory Species; Advisory Panel for Atlantic Highly Migratory Species Southeast...

Science.gov (United States)

2011-10-24

.... Virgin Islands and Puerto Rico, and each of the constituent interstate commissions: the Atlantic States... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration RIN 0648-XA776 Atlantic Highly Migratory Species; Advisory Panel for Atlantic Highly Migratory Species Southeast Data, Assessment...

77 FR 8776 - Fisheries of the Northeastern United States; Atlantic Bluefish Fishery; 2012 Atlantic Bluefish...

Science.gov (United States)

2012-02-15

.... 120201086-2085-01] RIN 0648-XA904 Fisheries of the Northeastern United States; Atlantic Bluefish Fishery; 2012 Atlantic Bluefish Specifications AGENCY: National Marine Fisheries Service (NMFS), National... comments. SUMMARY: NMFS proposes specifications for the 2012 Atlantic bluefish fishery, including an annual...

Mechanisms of northeastern Brazil rainfall anomalies due to Southern Tropical Atlantic variability

Science.gov (United States)

Neelin, J.; Su, H.

2004-05-01

Observational studies have shown that the rainfall anomalies in eastern equatorial South America, including Nordeste Brazil, have a positive correlation with tropical southern Atlantic sea surface temperature (SST) anomalies. Such relationships are reproduced in model simulations with the quasi-equilibrium tropical circulation model (QTCM), which includes a simple land model. A suite of model ensemble experiments is analysed using observed SST over the tropical oceans, the tropical Atlantic and the tropical southern Atlantic (30S-0), respectively (with climatological SST in the remainder of the oceans). Warm tropical south Atlantic SST anomalies yield positive precipitation anomalies over the Nordeste and the southern edge of the Atlantic marine intertropical convergence zone (ITCZ). Mechanisms associated with moisture variations are responsible for the land precipitation changes. Increases in moisture over the Atlantic cause positive anomalies in moisture advection, spreading increased moisture downwind. Where the basic state is far from the convective stability threshold, moisture changes have little effect, but the margins of the climatological convection zone are affected. The increased moisture supply due to advection is enhanced by increases in low-level convergence required by moist static energy balances. The moisture convergence term is several times larger, but experiments altering the moisture advection confirm that the feedback is initiated by wind acting on moisture gradient. This mechanism has several features in common with the recently published "upped-ante" mechanism for El Nino impacts on this region. In that case, the moisture gradient is initiated by warm free tropospheric temperature anomalies increasing the typical value of low-level moisture required to sustain convection in the convection zones. Both mechanisms suggest the usefulness of coordinating ocean and land in situ observations of boundary layer moisture.

Regional differentiation and post-glacial expansion of the Atlantic silverside, Menidia menidia, an annual fish with high dispersal potential

OpenAIRE

Mach, Megan E.; Sbrocco, Elizabeth J.; Hice, Lyndie A.; Duffy, Tara A.; Conover, David O.; Barber, Paul H.

2010-01-01

The coastal marine environment of the Northwest Atlantic contains strong environmental gradients that create distinct marine biogeographic provinces by limiting dispersal, recruitment, and survival. This region has also been subjected to numerous Pleistocene glacial cycles, resulting in repeated extirpations and recolonizations in northern populations of marine organisms. In this study, we examined patterns of genetic structure and historical demography in the Atlantic silverside, Menidia men...

78 FR 27956 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Amendment 39 to the Fishery...

Science.gov (United States)

2013-05-13

... environmental impact statement (DEIS); notice of public hearings; request for comments. SUMMARY: NMFS, Southeast... comments received on the DEIS in developing the final environmental impact statement (FEIS) and before... the Caribbean, Gulf of Mexico, and South Atlantic; Amendment 39 to the Fishery Management Plan for the...

78 FR 66900 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Amendment 28 to the Fishery...

Science.gov (United States)

2013-11-07

... environmental impact statement (DEIS); scoping; request for comments. SUMMARY: NMFS, Southeast Region, in... received on the DEIS in developing the final environmental impact statement (FEIS), and before voting to... the Caribbean, Gulf of Mexico, and South Atlantic; Amendment 28 to the Fishery Management Plan for the...

77 FR 25144 - Fisheries of the South Atlantic; South Atlantic Fishery Management Council; Public Meetings

Science.gov (United States)

2012-04-27

.... The Council will consider input from the workgroup and workshops during its June meeting in Orlando... Atlantic; South Atlantic Fishery Management Council; Public Meetings AGENCY: National Marine Fisheries... public meeting and public workshop. SUMMARY: The South Atlantic Fishery Management Council (Council) will...

77 FR 25100 - Fisheries of the Northeastern United States; Atlantic Bluefish Fishery; 2012 Atlantic Bluefish...

Science.gov (United States)

2012-04-27

.... 120201086-2418-02] RIN 0648-XA904 Fisheries of the Northeastern United States; Atlantic Bluefish Fishery; 2012 Atlantic Bluefish Specifications AGENCY: National Marine Fisheries Service (NMFS), National... specifications for the 2012 Atlantic bluefish fishery, including an annual catch limit, total allowable landings...

78 FR 11809 - Fisheries of the Northeastern United States; Atlantic Bluefish Fishery; 2013-2014 Atlantic...

Science.gov (United States)

2013-02-20

.... 130104009-3099-01] RIN 0648-XC432 Fisheries of the Northeastern United States; Atlantic Bluefish Fishery; 2013-2014 Atlantic Bluefish Specifications AGENCY: National Marine Fisheries Service (NMFS), National... comments. SUMMARY: NMFS proposes specifications for the 2013 and 2014 Atlantic bluefish fishery, including...

77 FR 21015 - Atlantic Highly Migratory Species; Atlantic Bluefin Tuna Fisheries

Science.gov (United States)

2012-04-09

... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 635 [Docket No. 110210132-1275-02] RIN 0648-XB116 Atlantic Highly Migratory Species; Atlantic Bluefin Tuna Fisheries AGENCY... to their ability to attract customers. In addition, 2011 Large Pelagics Survey estimates indicate...

76 FR 18416 - Atlantic Highly Migratory Species; Atlantic Bluefin Tuna Fisheries

Science.gov (United States)

2011-04-04

... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 635 [Docket No. 100317152-0176-01] RIN 0648-XA327 Atlantic Highly Migratory Species; Atlantic Bluefin Tuna Fisheries AGENCY... ability to attract customers. In addition, recent Large Pelagics Survey estimates indicate that charter...

78 FR 65974 - Atlantic Highly Migratory Species; Advisory Panel for Atlantic Highly Migratory Species Southeast...

Science.gov (United States)

2013-11-04

... Management Councils, the 18 states in the Atlantic and Gulf of Mexico, both the U.S. Virgin Islands and... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration RIN 0648-XC935 Atlantic Highly Migratory Species; Advisory Panel for Atlantic Highly Migratory Species Southeast Data, Assessment...

76 FR 14378 - Fisheries of the South Atlantic; South Atlantic Fishery Management Council; Public Meeting

Science.gov (United States)

2011-03-16

... the South Atlantic; South Atlantic Fishery Management Council; Public Meeting AGENCY: National Marine... the Coastal Migratory Pelagics Fishery Management Plan (FMP) for the South Atlantic and Gulf of Mexico... AP will also review Amendment 19 to the Coastal Migratory Pelagics FMP regarding alternatives for bag...

78 FR 20258 - Atlantic Highly Migratory Species; Atlantic Bluefin Tuna Fisheries

Science.gov (United States)

2013-04-04

... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 635 [Docket No. 120306154-2241-02] RIN 0648-XC593 Atlantic Highly Migratory Species; Atlantic Bluefin Tuna Fisheries AGENCY... retention limit is vital to their ability to attract customers. In addition, 2012 Large Pelagics Survey...

Global Warming In A Regional Model of The Atlantic Ocean - Echam4/opyc3 In Flame 4/3

Science.gov (United States)

Schweckendiek, U.; Willebrand, J.

The reaction of the Thermohaline Circulation (THC) in most climate models on global warming scenarios is a weakening of the THC. An exception is the ECHAM4/OPYC3 simulation whose stable behaviour is traced back to a strongly enhanced evaporation and as a consequence to a development of a salt anomaly in the tropics and subtropics of the Atlantic Ocean (Latif et al.,2000). This salt signal is advected into convection regions and compensates the reduction of surface density due to surface heating and freshening. To examine this scenario for a more realistic ocean model, data from this model is used to drive a reginal model of the Atlantic Ocean. In order to test the crucial mechanisms for the maintainance of the meridional overturning, we have performed sensitivity studies by focussing on different combinations of the anomalous freshwater and heat fluxes. The results demonstrate that for the stabilising effect to become effective the salt sig- nal has to enter the GIN-Seas and subsequently the overflow waters, underlining the importance of the overflows for the THC. The Labrador Sea Convection is however uneffected by this stabilising salt signal and its convection ultimatly breaks down un- der surface warming and freshening.

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.

Simulated variability of the Atlantic meridional overturning circulation

Science.gov (United States)

Bentsen, M.; Drange, H.; Furevik, T.; Zhou, T.

To examine the multi-annual to decadal scale variability of the Atlantic Meridional Overturning Circulation (AMOC) we conducted a four-member ensemble with a daily reanalysis forced, medium-resolution global version of the isopycnic coordinate ocean model MICOM, and a 300-years integration with the fully coupled Bergen Climate Model (BCM). The simulations of the AMOC with both model systems yield a long-term mean value of 18 Sv and decadal variability with an amplitude of 1-3 Sv. The power spectrum of the inter-annual to decadal scale variability of the AMOC in BCM generally follows the theoretical red noise spectrum, with indications of increased power near the 20-years period. Comparison with observational proxy indices for the AMOC, e.g. the thickness of the Labrador Sea Water, the strength of the baroclinic gyre circulation in the North Atlantic Ocean, and the surface temperature anomalies along the mean path of the Gulf Stream, shows similar trends and phasing of the variability, indicating that the simulated AMOC variability is robust and real. Mixing indices have been constructed for the Labrador, the Irminger and the Greenland-Iceland-Norwegian (GIN) seas. While convective mixing in the Labrador and the GIN seas are in opposite phase, and linked to the NAO as observations suggest, the convective mixing in the Irminger Sea is in phase with or leads the Labrador Sea. Newly formed deep water is seen as a slow, anomalous cold and fresh, plume flowing southward along the western continental slope of the Atlantic Ocean, with a return flow of warm and saline water on the surface. In addition, fast-travelling topographically trapped waves propagate southward along the continental slope towards equator, where they go east and continue along the eastern rim of the Atlantic. For both types of experiments, the Northern Hemisphere sea level pressure and 2 m temperature anomaly patterns computed based on the difference between climate states with strong and weak AMOC

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.

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.

Model evaluation methodology applicable to environmental assessment models

International Nuclear Information System (INIS)

Shaeffer, D.L.

1979-08-01

A model evaluation methodology is presented to provide a systematic framework within which the adequacy of environmental assessment models might be examined. The necessity for such a tool is motivated by the widespread use of models for predicting the environmental consequences of various human activities and by the reliance on these model predictions for deciding whether a particular activity requires the deployment of costly control measures. Consequently, the uncertainty associated with prediction must be established for the use of such models. The methodology presented here consists of six major tasks: model examination, algorithm examination, data evaluation, sensitivity analyses, validation studies, and code comparison. This methodology is presented in the form of a flowchart to show the logical interrelatedness of the various tasks. Emphasis has been placed on identifying those parameters which are most important in determining the predictive outputs of a model. Importance has been attached to the process of collecting quality data. A method has been developed for analyzing multiplicative chain models when the input parameters are statistically independent and lognormally distributed. Latin hypercube sampling has been offered as a promising candidate for doing sensitivity analyses. Several different ways of viewing the validity of a model have been presented. Criteria are presented for selecting models for environmental assessment purposes

2005 Atlantic Hurricanes Poster

Data.gov (United States)

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

Northeast Atlantic blue whiting

OpenAIRE

Heino, Mikko

2010-01-01

Heino, M. 2010. Northeast Atlantic blue whiting. In Life cycle spatial patterns of small pelagic fish in the Northeast Atlantic, pp. 59-64. Ed by P. Petitgas. ICES Cooperative Research Report 306. ICES, Copenhagen.

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.)

A Study of Mesoscale Gravity Waves over the North Atlantic with Satellite Observations and a Mesoscale Model

Science.gov (United States)

Wu, Dong L.; Zhang, Fuqing

2004-01-01

Satellite microwave data are used to study gravity wave properties and variabilities over the northeastern United States and the North Atlantic in the December-January periods. The gravity waves in this region, found in many winters, can reach the stratopause with growing amplitude. The Advanced Microwave Sounding Unit-A (AMSU-A) observations show that the wave occurrences are correlated well with the intensity and location of the tropospheric baroclinic jet front systems. To further investigate the cause(s) and properties of the North Atlantic gravity waves, we focus on a series of wave events during 19-21 January 2003 and compare AMSU-A observations to simulations from a mesoscale model (MM5). The simulated gravity waves compare qualitatively well with the satellite observations in terms of wave structures, timing, and overall morphology. Excitation mechanisms of these large-amplitude waves in the troposphere are complex and subject to further investigations.

75 FR 54597 - Fisheries of the South Atlantic; Southeast Data, Assessment, and Review (SEDAR); South Atlantic...

Science.gov (United States)

2010-09-08

... Atlantic, and Caribbean Fishery Management Councils, in conjunction with NOAA Fisheries and the Atlantic... are appointed by the Gulf of Mexico, South Atlantic, and Caribbean Fishery Management Councils; the..., environmentalists, and NGO's; International experts; and staff of Councils, Commissions, and state and federal...

78 FR 26523 - Fisheries of the Northeastern United States; Atlantic Bluefish Fishery; 2013 and 2014 Atlantic...

Science.gov (United States)

2013-05-07

.... 130104009-3416-02] RIN 0648-XC432 Fisheries of the Northeastern United States; Atlantic Bluefish Fishery; 2013 and 2014 Atlantic Bluefish Specifications AGENCY: National Marine Fisheries Service (NMFS... final specifications for the 2013 and 2014 Atlantic bluefish fishery, including annual catch limits...

A minimal model of the Atlantic Multidecadal Variability: its genesis and predictability

Energy Technology Data Exchange (ETDEWEB)

Ou, Hsien-Wang [Lamont-Doherty Earth Observatory of Columbia University, Department of Earth and Environmental Sciences, Palisades, NY (United States)

2012-02-15

Through a box model of the subpolar North Atlantic, we examine the genesis and predictability of the Atlantic Multidecadal Variability (AMV), posited as a linear perturbation sustained by the stochastic atmosphere. Postulating a density-dependent thermohaline circulation (THC), the latter would strongly differentiate the thermal and saline damping, and facilitate a negative feedback between the two fields. This negative feedback preferentially suppresses the low-frequency thermal variance to render a broad multidecadal peak bounded by the thermal and saline damping time. We offer this ''differential variance suppression'' as an alternative paradigm of the AMV in place of the ''damped oscillation'' - the latter generally not allowed by the deterministic dynamics and in any event bears no relation to the thermal peak. With the validated dynamics, we then assess the AMV predictability based on the relative entropy - a difference of the forecast and climatological probability distributions, which decays through both error growth and dynamical damping. Since the stochastic forcing is mainly in the surface heat flux, the thermal noise grows rapidly and together with its climatological variance limited by the THC-aided thermal damping, they strongly curtail the thermal predictability. The latter may be prolonged if the initial thermal and saline anomalies are of the same sign, but even rare events of less than 1% chance of occurrence yield a predictable time that is well short of a decade; we contend therefore that the AMV is in effect unpredictable. (orig.)

Otolith chemistry discriminates natal signatures of yellowfin tuna (Thunnus albacares) in the Atlantic Ocean

Science.gov (United States)

Kitchens, L. L.; Rooker, J. R.

2016-02-01

In this study, the otolith chemistry of young-of-the-year (YOY) yellowfin tuna (Thunnus albacares) was examined to determine whether chemical signatures are distinct across different putative spawning areas in the Atlantic Ocean. Yellowfin tuna is a highly migratory species that is currently managed as a single panmictic stock in the Atlantic Ocean; however, uncertainty remains regarding the population structure of yellowfin in this region, particularly concerning the degree of mixing between spawning populations. Analysis of naturally occurring chemical tracers in otoliths provides a valuable means to reconstruct a fish's environmental history and is thus a promising approach for delineating stock structure of Atlantic yellowfin tuna. YOY yellowfin tuna otoliths were collected from 5 locations in the Atlantic Ocean (Gulf of Mexico, SE Caribbean, Brazil, Cape Verde, and Gulf of Guinea) from 2013-2015 and trace element (Li, Mg, Mn, Co, Cu, Sr, Zn, and Ba) and stable isotope (δ13C and δ18O) analyses were conducted to investigate regional variation in otolith chemical composition. Results show significant differences among nursery areas in both trace element (MANOVA, p<0.001) and δ13C and δ18O signatures (ANOVA, p=0.017 and p=0.001, respectively). Particularly high spatial separation was observed based on eastern Atlantic (Gulf of Guinea + Cape Verde) and western Atlantic (Gulf of Mexico + Brazil + Martinique) nursery areas, indicating the approach has promise for distinguishing migrants displaying trans-ocean movement. These chemical signatures will be used to assign adult yellowfin tuna to their nursery of origin, ultimately providing an improved understanding of the stock structure and movement of yellowfin tuna in the Atlantic Ocean.

Atlantic Warm Pool Trigger for the Younger Dryas Climate Event

Science.gov (United States)

Abdul, N. A.; Mortlock, R. A.; Wright, J. D.; Fairbanks, R. G.; Teneva, L. T.

2011-12-01

There is growing evidence that variability in the size and heat content of the tropical Atlantic Warm Pool impacts circum-North Atlantic climate via the Atlantic Multi-decadal Oscillation mode (Wang et al., 2008). The Atlantic Warm Pool spans the Gulf of Mexico, Caribbean Sea and the western tropical North Atlantic. Barbados is located near the center of the tropical Atlantic Warm Pool and coupled ocean models suggest that Barbados remains near the center of the tropical Atlantic Warm Pool under varying wind stress simulations. Measurements of the oxygen isotope paleothermometer in Acropora palmata coral species recovered from cores offshore Barbados, show a 3oC monotonic decrease in sea surface temperature from 13106 ± 83 to 12744 ± 61 years before present (errors given as 2 sigma). This interval corresponds to a sea level rise from 71.4 meters to 67.1 meters below present levels at Barbados. The 3oC temperature decrease is captured in eight A. palmata specimens that are in stratigraphic sequence, 230Th/234U dated, and analyzed for oxygen isotopes. All measurements are replicated. We are confident that this is the warm pool equivalent of the Younger Dryas climate event. The initiation of this temperature drop in the Atlantic Warm Pool predates the Younger Dryas start in Greenland ice cores, reported to start at 12896 ± 138 years (relative to AD 2000) (Rasmussen et al., 2006), while few other Younger Dryas climate records are dated with similar accuracy to make the comparison. Rasmussen, S.O., Andersen, K.K., Svensson, A.M., Steffensen, J.P., Vinther, B.M., Clausen, H.B., Siggaard-Andersen, M.L., Johnsen, S.J., Larsen, L.B., Dahl-Jensen, D., Bigler, M., Röthlisberger, R., Fischer, H., Goto-Azuma, K., Hansson, M.E., and Ruth, U., 2006, A new Greenland ice core chronology for the last glacial termination: J. Geophys. Res., v. 111, p. D06102. Wang, C., Lee, S.-K., and Enfield, D.B., 2008, Atlantic Warm Pool acting as a link between Atlantic Multidecadal

Phytoplankton biovolume is independent from the slope of the size spectrum in the oligotrophic atlantic ocean

KAUST Repository

Moreno-Ostos, Enrique

2015-08-06

Modelling the size-abundance spectrum of phytoplankton has proven to be a very useful tool for the analysis of physical-biological coupling and the vertical flux of carbon in oceanic ecosystems at different scales. A frequent observation relates high phytoplankton biovolume in productive regions with flatter spectrum slope and the opposite in oligotrophic ecosystems. Rather than this, the relationship between high biovolume phytoplankton assemblages and flatter size-abundance spectra does not correspond with measurements of the phytoplankton community in the Atlantic Ocean open waters. As part of the Malaspina Circunnavegation Expedition, sixty seven sampling stations within the Atlantic Ocean covering six oceanographic provinces, at different seasons, produced a complete set of phytoplankton size-spectra whose slope and biovolume did not show any obvious interrelation. In these oligotrophic sites, small (procaryotes) and medium-size (nanoplankton) cells are responsible for the most part of biovolume, and their response to environmental conditions does not apply to changes in the size-abundance spectrum slope as expected in richer, large-cell dominated ecosystems.

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

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.

Environmental Effects of Offshore Wind Development. Fiscal Year 2012 Progress Report

Energy Technology Data Exchange (ETDEWEB)

Copping, Andrea E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hanna, Luke A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Butner, R. Scott [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Carlson, Thomas J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Halvorsen, Michele B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Duberstein, Corey A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Matzner, Shari [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Whiting, Jonathan M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Blake, Kara M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stavole, Jessica [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2012-09-01

Potential environmental effects of offshore wind (OSW) energy projects are not well understood, and regulatory agencies are required to make decisions in spite of substantial uncertainty about environmental impacts and their long-term consequences. An understanding of risks associated with interactions between OSW installations and aquatic receptors, including animals, habitats, and ecosystems, can help define key uncertainties and focus regulatory actions and scientific studies on interactions of most concern. To examine the environmental risks associated with OSW developments in the U.S. Pacific Northwest National Laboratory (PNNL) focused on the following four priority research areas in FY 2012: • Environmental Risk Evaluation System (ERES) - Followed project developments on the two OSW projects that PNNL screened in FY 2011 for environmental consequence: Fishermen’s Energy off the coast of Atlantic City, NJ and LEEDCo. near Cleveland, OH in Lake Erie. • Tethys - Developed a smart knowledge base which houses environmental research, data and information pertaining to OSW energy: • Technical Assessment - Produced a new software to create an automated process of identifying and differentiating between flying organism such as birds and bats by using thermal imagery; and • North Atlantic Right Whales - Developed an environmental risk management system to mitigate the impacts on North Atlantic Right Whales (NARW) during installation and piledriving stages of OSW developments. By identifying and addressing the highest priority environmental risks for OSW devices and associated installations the ERES process assists project proponents, regulators, and stakeholders to engage in the most efficient and effective siting and permitting pathways.

A multimodel assessment of future projections of North Atlantic and European extratropical cyclones in the CMIP5 climate models

OpenAIRE

Zappa, Giuseppe; Shaffrey, Len C.; Hodges, Kevin I.; Sansom, Phil G.; Stephenson, David B.

2013-01-01

The response of North Atlantic and European extratropical cyclones to climate change is investigated in the climate models participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5). In contrast to previous multimodel studies, a feature-tracking algorithm is here applied to separately quantify the re- sponses in the number, the wind intensity, and the precipitation intensity of extratropical cyclones. Moreover, a statistical framework is employed to formally assess the unce...

Magnetization modeling in the north and equatorial Atlantic Ocean using MAGSAT data

Science.gov (United States)

Hayling, K. L.; Harrison, C. G. A.

1986-01-01

Magsat 2 x 2-deg scalar anomalous-magnetic-field data (Langel et al., 1982) for the northern and equatorial Atlantic are inverted and combined with physiographic data and laboratory results on the magnetization of oceanic rocks and the oceanic crust to construct models explaining the shorter-wavelength component of the anomalies. An annihilator is applied to the inversion results to eliminate reverse-magnetized sources and facilitate comparisons of areas inverted separately, and a latitude effect on source spacing is tentatively attributed to greater noise contamination at lower latitudes. It is found that remanent magnetization combined with considerable crustal thickening can best explain the high intensity levels observed, although viscous magnetization or contamination of the data by noncrustal sources must also be considered.

Proposing an Environmental Excellence Self-Assessment Model

DEFF Research Database (Denmark)

Meulengracht Jensen, Peter; Johansen, John; Wæhrens, Brian Vejrum

2013-01-01

that the EEA model can be used in global organizations to differentiate environmental efforts depending on the maturity stage of the individual sites. Furthermore, the model can be used to support the decision-making process regarding when organizations should embark on more complex environmental efforts......This paper presents an Environmental Excellence Self-Assessment (EEA) model based on the structure of the European Foundation of Quality Management Business Excellence Framework. Four theoretical scenarios for deploying the model are presented as well as managerial implications, suggesting...

Aerosol-Cloud Interactions in the South-East Atlantic: Knowledge Gaps, Planned Observations to Address Them, and Implications for Global Climate Change Modeling

Science.gov (United States)

Redemann, Jens; Wood, R.; Zuidema, P.; Haywood, J.; Luna, B.; Abel, S.

2015-01-01

Southern Africa produces almost a third of the Earth's biomass burning (BB) aerosol particles, yet the fate of these particles and their influence on regional and global climate is poorly understood. Particles lofted into the mid-troposphere are transported westward over the South-East (SE) Atlantic, home to one of the three permanent subtropical Stratocumulus (Sc) cloud decks in the world. The stratocumulus "climate radiators" are critical to the regional and global climate system. They interact with dense layers of BB aerosols that initially overlay the cloud deck, but later subside and are mixed into the clouds. These interactions include adjustments to aerosol-induced solar heating and microphysical effects. As emphasized in the latest IPCC report, the global representation of these aerosol-cloud interaction processes in climate models is one of the largest uncertainty in estimates of future climate. Hence, new observations over the SE Atlantic have significant implications for global climate change scenarios. We discuss the current knowledge of aerosol and cloud property distributions based on satellite observations and sparse suborbital sampling, and describe planned field campaigns in the region. Specifically, we describe the scientific objectives and implementation of the following four synergistic, international research activities aimed at providing a process-level understanding of aerosol-cloud interactions over the SE Atlantic: 1) ORACLES (Observations of Aerosols above Clouds and their interactions), a five-year investigation between 2015 and 2019 with three Intensive Observation Periods (IOP), recently funded by the NASA Earth-Venture Suborbital Program, 2) CLARIFY-2016 (Cloud-Aerosol-Radiation Interactions and Forcing: Year 2016), a comprehensive observational and modeling programme funded by the UK's Natural Environment Research Council (NERC), and supported by the UK Met Office. 3) LASIC (Layered Atlantic Smoke Interactions with Clouds), a funded

Cold-season atmospheric response to the natural variability of the Atlantic meridional overturning circulation

Energy Technology Data Exchange (ETDEWEB)

Gastineau, Guillaume; Frankignoul, Claude [LOCEAN/IPSL, Universite Pierre et Marie Curie, 4 place Jussieu, BP100, Paris Cedex 05 (France)

2012-07-15

The influence of the natural variability of the Atlantic meridional overturning circulation (AMOC) on the atmosphere is studied in multi-centennial simulations of six global climate models, using Maximum Covariance Analysis (MCA). In all models, a significant but weak influence of the AMOC changes is found during the Northern Hemisphere cold-season, when the ocean leads the atmosphere by a few years. Although the oceanic pattern slightly varies, an intensification of the AMOC is followed in all models by a weak sea level pressure response that resembles a negative phase of the North Atlantic Oscillation (NAO). The signal amplitude is typically 0.5 hPa and explains about 10% of the yearly variability of the NAO in all models. The atmospheric response seems to be due primarily due to an increase of the heat loss along the North Atlantic Current and the subpolar gyre, associated with an AMOC-driven warming. Sea-ice changes appear to be less important. The stronger heating is associated to a southward shift of the lower-tropospheric baroclinicity and a decrease of the eddy activity in the North Atlantic storm track, which is consistent with the equivalent barotropic perturbation resembling the negative phase of the NAO. This study thus provides some evidence of an atmospheric signature of the AMOC in the cold-season, which may have some implications for the decadal predictability of climate in the North Atlantic region. (orig.)

Integrating Archival Tag Data and a High-Resolution Oceanographic Model to Estimate Basking Shark (Cetorhinus maximus Movements in the Western Atlantic

Directory of Open Access Journals (Sweden)

Camrin D. Braun

2018-02-01

Full Text Available Basking shark (Cetorhinus maximus populations are considered “vulnerable” globally and “endangered” in the northeast Atlantic by the International Union for the Conservation of Nature (IUCN. Much of our knowledge of this species comes from surface observations in coastal waters, yet recent evidence suggests the majority of their lives may be spent in the deep ocean. Depth preferences of basking sharks have significantly limited movement studies that used pop-up satellite archival transmitting (PSAT tags as conventional light-based geolocation is impossible for tagged animals that spend significant time below the photic zone. We tagged 57 basking sharks with PSAT tags in the NW Atlantic from 2004 to 2011. Many individuals spent several months at meso- and bathy-pelagic depths where accurate light-level geolocation was impossible during fall, winter and spring. We applied a newly-developed geolocation approach for the PSAT data by comparing three-dimensional depth-temperature profile data recorded by the tags to modeled in situ oceanographic data from the high-resolution HYbrid Coordinate Ocean Model (HYCOM. Observation-based likelihoods were leveraged within a state-space hidden Markov model (HMM. The combined tracks revealed that basking sharks moved from waters around Cape Cod, MA to as far as the SE coast of Brazil (20°S, a total distance of over 17,000 km. Moreover, 59% of tagged individuals with sufficient deployment durations (>250 days demonstrated seasonal fidelity to Cape Cod and the Gulf of Maine, with one individual returning to within 60 km of its tagging location 1 year later. Tagged sharks spent most of their time at epipelagic depths during summer months around Cape Cod and in the Gulf of Maine. During winter months, sharks spent extended periods at depths of at least 600 m while moving south to the Sargasso Sea, the Caribbean Sea, or the western tropical Atlantic. Our work demonstrates the utility of applying advances in

CARINA TCO2 data in the Atlantic Ocean

Directory of Open Access Journals (Sweden)

R. Wanninkhof

2010-07-01

Full Text Available Water column data of carbon and carbon-relevant hydrographic and hydrochemical parameters from 188 cruises in the Arctic Mediterranean Seas, Atlantic and Southern Ocean have been retrieved and merged in a new data base: the CARINA (CARbon IN the Atlantic Project. These data have gone through rigorous quality control (QC procedures so as to improve the quality and consistency of the data as much as possible. Secondary quality control, which involved objective study of data in order to quantify systematic differences in the reported values, was performed for the pertinent parameters in the CARINA data base. Systematic biases in the data have been tentatively corrected in the data products. The products are three merged data files with measured, adjusted and interpolated data of all cruises for each of the three CARINA regions (Arctic Mediterranean Seas, Atlantic and Southern Ocean. Ninety-eight cruises were conducted in the "Atlantic" defined as the region south of the Greenland-Iceland-Scotland Ridge and north of about 30° S. Here we report the details of the secondary QC which was done on the total dissolved inorganic carbon (TCO2 data and the adjustments that were applied to yield the final data product in the Atlantic. Procedures of quality control – including crossover analysis between stations and inversion analysis of all crossover data – are briefly described. Adjustments were applied to TCO2 measurements for 17 of the cruises in the Atlantic Ocean region. With these adjustments, the CARINA data base is consistent both internally as well as with GLODAP data, an oceanographic data set based on the WOCE Hydrographic Program in the 1990s, and is now suitable for accurate assessments of, for example, regional oceanic carbon inventories, uptake rates and model validation.

A qualitative model of the salmon life cycle in the context of river rehabilitation

NARCIS (Netherlands)

Noble, R.A.A.; Bredeweg, B.; Linnebank, F.; Salles, P.; Cowx, I.G.; Žabkar, J.; Bratko, I.

2009-01-01

A qualitative model was developed in Garp3 to capture and formalise knowledge about river rehabilitation and the management of an Atlantic salmon population. The model integrates information about the ecology of the salmon life cycle, the environmental factors that may limit the survival of key life

77 FR 15721 - Fisheries of the South Atlantic and Gulf of Mexico; South Atlantic Fishery Management Council...

Science.gov (United States)

2012-03-16

... the South Atlantic and Gulf of Mexico; South Atlantic Fishery Management Council; Public Meeting...), Commerce. ACTION: Notice of a public meeting. SUMMARY: The South Atlantic Fishery Management Council (SAFMC... Biological Catch (ABC) values for managed stocks including the effect of revised recreational catch estimates...

Frequency Dependent Nudging of Hydrographic Data Into a Numerical Model of the North Atlantic

Science.gov (United States)

Thompson, K. R.; Wright, D. G.

2002-12-01

Nudging is one of the simplest ways of assimilating data into ocean models and it has been used for many years in studies of large-scale ocean circulation. One of its drawbacks is the suppression of eddies when nudging an eddy-permitting ocean model strongly toward an observed seasonal climatology. We propose a straightforward extension of nudging in which the model's climatology, rather than its instantaneous state, is nudged toward the observed seasonal climatology. In effect we propose nudging in specific frequency bands that are centered on the discrete frequencies evident in the observed climatology (e.g. 0, 1/12 and 1/6 cycles per month). This extension of conventional nudging allows the difference between the observed and modeled climatologies arbitrarily to be made small while allowing variations outside the selected frequency bands to evolve freely. We show how the method can be implemented efficiently in complex models using a Kalman filter and also discuss the benefits of spatially smoothing the nudges. We conclude with a demonstration of frequency dependent nudging using a 1/3 degree model of the North Atlantic.

75 FR 7435 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic...

Science.gov (United States)

2010-02-19

.... 100105009-0053-01] RIN 0648-AY51 Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic Deep-Sea Red Crab Specifications AGENCY: National Marine Fisheries Service (NMFS... comments. SUMMARY: NMFS proposes 2010 specifications for the Atlantic deep-sea red crab fishery, including...

Towards policy relevant environmental modeling: contextual validity and pragmatic models

Science.gov (United States)

Miles, Scott B.

2000-01-01

"What makes for a good model?" In various forms, this question is a question that, undoubtedly, many people, businesses, and institutions ponder with regards to their particular domain of modeling. One particular domain that is wrestling with this question is the multidisciplinary field of environmental modeling. Examples of environmental models range from models of contaminated ground water flow to the economic impact of natural disasters, such as earthquakes. One of the distinguishing claims of the field is the relevancy of environmental modeling to policy and environment-related decision-making in general. A pervasive view by both scientists and decision-makers is that a "good" model is one that is an accurate predictor. Thus, determining whether a model is "accurate" or "correct" is done by comparing model output to empirical observations. The expected outcome of this process, usually referred to as "validation" or "ground truthing," is a stamp on the model in question of "valid" or "not valid" that serves to indicate whether or not the model will be reliable before it is put into service in a decision-making context. In this paper, I begin by elaborating on the prevailing view of model validation and why this view must change. Drawing from concepts coming out of the studies of science and technology, I go on to propose a contextual view of validity that can overcome the problems associated with "ground truthing" models as an indicator of model goodness. The problem of how we talk about and determine model validity has much to do about how we perceive the utility of environmental models. In the remainder of the paper, I argue that we should adopt ideas of pragmatism in judging what makes for a good model and, in turn, developing good models. From such a perspective of model goodness, good environmental models should facilitate communication, convey—not bury or "eliminate"—uncertainties, and, thus, afford the active building of consensus decisions, instead

Predictions of models for environmental radiological assessment

International Nuclear Information System (INIS)

Peres, Sueli da Silva; Lauria, Dejanira da Costa; Mahler, Claudio Fernando

2011-01-01

In the field of environmental impact assessment, models are used for estimating source term, environmental dispersion and transfer of radionuclides, exposure pathway, radiation dose and the risk for human beings Although it is recognized that the specific information of local data are important to improve the quality of the dose assessment results, in fact obtaining it can be very difficult and expensive. Sources of uncertainties are numerous, among which we can cite: the subjectivity of modelers, exposure scenarios and pathways, used codes and general parameters. The various models available utilize different mathematical approaches with different complexities that can result in different predictions. Thus, for the same inputs different models can produce very different outputs. This paper presents briefly the main advances in the field of environmental radiological assessment that aim to improve the reliability of the models used in the assessment of environmental radiological impact. The intercomparison exercise of model supplied incompatible results for 137 Cs and 60 Co, enhancing the need for developing reference methodologies for environmental radiological assessment that allow to confront dose estimations in a common comparison base. The results of the intercomparison exercise are present briefly. (author)

75 FR 49420 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic...

Science.gov (United States)

2010-08-13

.... 100513223-0289-02] RIN 0648-AY88 Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic Deep-Sea Red Crab Specifications In- season Adjustment AGENCY: National Marine...-sea (DAS) allocation for the Atlantic deep- sea red crab fishery that were implemented in May 2010...

The influence of the Atlantic Warm Pool on the Florida panhandle sea breeze

Science.gov (United States)

Misra, Vasubandhu; Moeller, Lauren; Stefanova, Lydia; Chan, Steven; O'Brien, James J.; Smith, Thomas J.; Plant, Nathaniel

2011-01-01

In this paper we examine the variations of the boreal summer season sea breeze circulation along the Florida panhandle coast from relatively high resolution (10 km) regional climate model integrations. The 23 year climatology (1979–2001) of the multidecadal dynamically downscaled simulations forced by the National Centers for Environmental Prediction–Department of Energy (NCEP-DOE) Reanalysis II at the lateral boundaries verify quite well with the observed climatology. The variations at diurnal and interannual time scales are also well simulated with respect to the observations. We show from composite analyses made from these downscaled simulations that sea breezes in northwestern Florida are associated with changes in the size of the Atlantic Warm Pool (AWP) on interannual time scales. In large AWP years when the North Atlantic Subtropical High becomes weaker and moves further eastward relative to the small AWP years, a large part of the southeast U.S. including Florida comes under the influence of relatively strong anomalous low-level northerly flow and large-scale subsidence consistent with the theory of the Sverdrup balance. This tends to suppress the diurnal convection over the Florida panhandle coast in large AWP years. This study is also an illustration of the benefit of dynamic downscaling in understanding the low-frequency variations of the sea breeze.

External forcing as a metronome for Atlantic multidecadal variability

Science.gov (United States)

Otterå, Odd Helge; Bentsen, Mats; Drange, Helge; Suo, Lingling

2010-10-01

Instrumental records, proxy data and climate modelling show that multidecadal variability is a dominant feature of North Atlantic sea-surface temperature variations, with potential impacts on regional climate. To understand the observed variability and to gauge any potential for climate predictions it is essential to identify the physical mechanisms that lead to this variability, and to explore the spatial and temporal characteristics of multidecadal variability modes. Here we use a coupled ocean-atmosphere general circulation model to show that the phasing of the multidecadal fluctuations in the North Atlantic during the past 600 years is, to a large degree, governed by changes in the external solar and volcanic forcings. We find that volcanoes play a particularly important part in the phasing of the multidecadal variability through their direct influence on tropical sea-surface temperatures, on the leading mode of northern-hemisphere atmosphere circulation and on the Atlantic thermohaline circulation. We suggest that the implications of our findings for decadal climate prediction are twofold: because volcanic eruptions cannot be predicted a decade in advance, longer-term climate predictability may prove challenging, whereas the systematic post-eruption changes in ocean and atmosphere may hold promise for shorter-term climate prediction.

Layered Atlantic Smoke Interactions with Clouds (LASIC) Science Plan

Energy Technology Data Exchange (ETDEWEB)

Zuidema, P [University of Miami; Chiu, C [University of Reading; Fairall, CW [NOAA - Environmental Technology Laboratory; Ghan, SJ [Pacific Northwest National Laboratory; Kollias, P [Stony Brook University; McFarguhar, GM; Mechem, DB [University of Kansas; Romps, DM [Lawrence Berkeley National Laboratory; Wong, H; Yuter, SE [North Carolina State University; Alvarado, MJ [Atmospheric and Environmental Research, Inc.; DeSzoeke, SP; Feingold, G [NOAA - Earth System Research Laboratory; Haywood, JM; Lewis, ER [Brookhaven National Laboratory; McComiskey, A [National Oceanic and Atmospheric Administration; Redemann, J [NASA - Ames Research Center; Turner, DD [National Oceanic and Atmospheric Administration; Wood, R [University of Washington; Zhu, P [Florida International University

2015-12-01

Southern Africa is the world’s largest emitter of biomass-burning (BB) aerosols. Their westward transport over the remote southeast Atlantic Ocean colocates some of the largest atmospheric loadings of absorbing aerosol with the least examined of the Earth’s major subtropical stratocumulus decks. Global aerosol model results highlight that the largest positive top-of-atmosphere forcing in the world occurs in the southeast Atlantic, but this region exhibits large differences in magnitude and sign between reputable models, in part because of high variability in the underlying model cloud distributions. Many uncertainties contribute to the highly variable model radiation fields: the aging of shortwave-absorbing aerosol during transport, how much of the aerosol mixes into the cloudy boundary layer, and how the low clouds adjust to smoke-radiation and smoke-cloud interactions. In addition, the ability of the BB aerosol to absorb shortwave radiation is known to vary seasonally as the fuel type on land changes.

ENVIRONMENTAL AUDITING: AN INTEGRATED ENVIRONMENTAL ASSESSMENT OF THE U.S. MID-ATLANTIC REGION

Science.gov (United States)

Many of today's environmental problems are regional in scope and their effects overlap and interact. We developed a simple method to provide an integrated assessment of environmental conditions and estimate cumulative impacts across a large region, by combining data on land-cove...

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.

An Atlantic influence on Amazon rainfall

Energy Technology Data Exchange (ETDEWEB)

Yoon, Jin-Ho [University of Maryland, Department of Atmospheric and Oceanic Science, College Park, MD (United States); Zeng, Ning [University of Maryland, Earth System Science Interdisciplinary Center, College Park, MD (United States); University of Maryland, Department of Atmospheric and Oceanic Science, College Park, MD (United States)

2010-02-15

Rainfall variability over the Amazon basin has often been linked to variations in Pacific sea surface temperature (SST), and in particular, to the El Nino/Southern Oscillation (ENSO). However, only a fraction of Amazon rainfall variability can be explained by ENSO. Building upon the recent work of Zeng (Environ Res Lett 3:014002, 2008), here we provide further evidence for an influence on Amazon rainfall from the tropical Atlantic Ocean. The strength of the North Atlantic influence is found to be comparable to the better-known Pacific ENSO connection. The tropical South Atlantic Ocean also shows some influence during the wet-to-dry season transition period. The Atlantic influence is through changes in the north-south divergent circulation and the movement of the ITCZ following warm SST. Therefore, it is strongest in the southern part of the Amazon basin during the Amazon's dry season (July-October). In contrast, the ENSO related teleconnection is through anomalous east-west Walker circulation with largely concentrated in the eastern (lower) Amazon. This ENSO connection is seasonally locked to boreal winter. A complication due to the influence of ENSO on Atlantic SST causes an apparent North Atlantic SST lag of Amazon rainfall. Removing ENSO from North Atlantic SST via linear regression resolves this causality problem in that the residual Atlantic variability correlates well and is in phase with the Amazon rainfall. A strong Atlantic influence during boreal summer and autumn is particularly significant in terms of the impact on the hydro-ecosystem which is most vulnerable during the dry season, as highlighted by the severe 2005 Amazon drought. Such findings have implications for both seasonal-interannual climate prediction and understanding the longer-term changes of the Amazon rainforest. (orig.)

Atlantic menhaden adult tagging study

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Atlantic menhaden are a schooling forage fish species, which are subject to a large commercial purse seine fishery. Atlantic menhaden are harvested for reduction...

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.

Energy and externality environmental regional model

International Nuclear Information System (INIS)

Baldi, L.; Bianchi, A.; Peri, M.

2000-01-01

The use of environmental externalities in both territorial management and the direction of energy and environment, faces the difficulties arising from their calculation. The so-called MACBET regional model, which has been constructed for Lombardy, is a first brand new attempt to overcome them. MACBET is a calculation model to assess environmental and employment externalities connected to energy use [it

A commentary on the Atlantic meridional overturning circulation stability in climate models

Science.gov (United States)

Gent, Peter R.

2018-02-01

The stability of the Atlantic meridional overturning circulation (AMOC) in ocean models depends quite strongly on the model formulation, especially the vertical mixing, and whether it is coupled to an atmosphere model. A hysteresis loop in AMOC strength with respect to freshwater forcing has been found in several intermediate complexity climate models and in one fully coupled climate model that has very coarse resolution. Over 40% of modern climate models are in a bistable AMOC state according to the very frequently used simple stability criterion which is based solely on the sign of the AMOC freshwater transport across 33° S. In a recent freshwater hosing experiment in a climate model with an eddy-permitting ocean component, the change in the gyre freshwater transport across 33° S is larger than the AMOC freshwater transport change. This casts very strong doubt on the usefulness of this simple AMOC stability criterion. If a climate model uses large surface flux adjustments, then these adjustments can interfere with the atmosphere-ocean feedbacks, and strongly change the AMOC stability properties. AMOC can be shut off for many hundreds of years in modern fully coupled climate models if the hosing or carbon dioxide forcing is strong enough. However, in one climate model the AMOC recovers after between 1000 and 1400 years. Recent 1% increasing carbon dioxide runs and RCP8.5 future scenario runs have shown that the AMOC reduction is smaller using an eddy-resolving ocean component than in the comparable standard 1° ocean climate models.

Communication models in environmental health.

Science.gov (United States)

Guidotti, Tee L

2013-01-01

Communication models common in environmental health are not well represented in the literature on health communication. Risk communication is a systematic approach to conveying essential information about a specific environmental issue and a framework for thinking about community risk and the alternatives for dealing with it. Crisis communication is intended to provide essential information to people facing an emergency in order to mitigate its effects and to enable them to make appropriate decisions, and it is primarily used in emergency management. Corporate communication is intended to achieve a change in attitude or perception of an organization, and its role in environmental health is usually public relations or to rehabilitate a damaged reputation. Environmental health education is a more didactic approach to science education with respect to health and the environment. Social marketing uses conventional marketing methods to achieve a socially desirable purpose but is more heavily used in health promotion generally. Communication models and styles in environmental health are specialized to serve the needs of the field in communicating with the community. They are highly structured and executed in different ways but have in common a relative lack of emphasis on changing personal or lifestyle behavior compared with health promotion and public health in general and a tendency to emphasize content on specific environmental issues and decision frameworks for protecting oneself or the community through collective action.

Dual annual spawning races in Atlantic sturgeon.

Directory of Open Access Journals (Sweden)

Matthew T Balazik

Full Text Available Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus, Acipenseridae populations in the United States were listed as either endangered or threatened under the Endangered Species Act in 2012. Because of the endangered/threatened status, a better understanding of Atlantic sturgeon life-history behavior and habitat use is important for effective management. It has been widely documented that Atlantic sturgeon reproduction occurs from late winter to early summer, varying clinally with latitude. However, recent data show Atlantic sturgeon also spawn later in the year. The group that spawns later in the year seems to be completely separate from the spring spawning run. Recognition of the later spawning season has drastically modified estimates of the population status of Atlantic sturgeon in Virginia. With the combination of new telemetry data and historical documentation we describe a dual spawning strategy that likely occurs in various degrees along most, if not all, of the Atlantic sturgeon's range. Using new data combined with historical sources, a new spawning strategy emerges which managers and researchers should note when determining the status of Atlantic sturgeon populations and implementing conservation measures.

75 FR 50715 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures; Amendment 3

Science.gov (United States)

2010-08-17

... [Docket No. 080519678-0313-03] RIN 0648-AW65 Atlantic Highly Migratory Species; Atlantic Shark Management... for adjusting annual shark quotas based on over- and underharvests. This correction makes a change to...), instruction 12a revised 50 CFR 635.27 (b)(1)(i) through (v), relating to, among other things, pelagic shark...

Modelling environmental change in Europe: towards a model inventory (SEIS/Forward)

DEFF Research Database (Denmark)

Jaeger, Annekathrin; Henrichs, Thomas

This technical report provides a non-exhaustive overview of modelling tools currently available to simulate future environmental change at a European scale. Modelling tools have become an important cornerstone of environmental assessments, and play an important role in providing the data......, many of which have been used by the European Environment Agency in its recent environmental assessments and reports, a limited number of which are described in more detail. This review identifies gaps in the availability, accessibility and applicability of current modelling tools, and stresses the need...

The evolutionary history of Eugenia sect. Phyllocalyx (Myrtaceae) corroborates historically stable areas in the southern Atlantic forests.

Science.gov (United States)

de Oliveira Bünger, Mariana; Fernanda Mazine, Fiorella; Forest, Félix; Leandro Bueno, Marcelo; Renato Stehmann, João; Lucas, Eve J

2016-12-01

Eugenia sect. Phyllocalyx Nied. includes 14 species endemic to the Neotropics, mostly distributed in the Atlantic coastal forests of Brazil. Here the first comprehensive phylogenetic study of this group is presented, and this phylogeny is used as the basis to evaluate the recent infrageneric classification in Eugenia sensu lato (s.l.) to test the history of the evolution of traits in the group and test hypotheses associated with the history of this clade. A total of 42 taxa were sampled, of which 14 were Eugenia sect. Phyllocalyx for one nuclear (ribosomal internal transcribed spacer) and four plastid markers (psbA-trnH, rpl16, trnL-rpl32 and trnQ-rps16). The relationships were reconstructed based on Bayesian analysis and maximum likelihood. Additionally, ancestral area analysis and modelling methods were used to estimate species dispersal, comparing historically climatic stable (refuges) and unstable areas. Maximum likelihood and Bayesian inferences indicate that Eugenia sect. Phyllocalyx is paraphyletic and the two clades recovered are characterized by combinations of morphological characters. Phylogenetic relationships support a link between Cerrado and south-eastern species and a difference in the composition of species from north-eastern and south-eastern Atlantic forest. Refugia and stable areas identified within unstable areas suggest that these areas were important to maintain diversity in the Atlantic forest biodiversity hotspot. This study provides a robust phylogenetic framework to address important historical questions for Eugenia s.l. within an evolutionary context, supporting the need for better taxonomic study of one of the largest genera in the Neotropics. Furthermore, valuable insight is offered into diversification and biome shifts of plant species in the highly environmentally impacted Atlantic forest of South America. Evidence is presented that climate stability in the south-eastern Atlantic forest during the Quaternary contributed to the

Bird distributional patterns support biogeographical histories and are associated with bioclimatic units in the Atlantic Forest, Brazil.

Science.gov (United States)

Carvalho, Cristiano DE Santana; Nascimento, Nayla Fábia Ferreira DO; Araujo, Helder F P DE

2017-10-17

Rivers as barriers to dispersal and past forest refugia are two of the hypotheses proposed to explain the patterns of biodiversity in the Atlantic Forest. It has recently been shown that possible past refugia correspond to bioclimatically different regions, so we tested whether patterns of shared distribution of bird taxa in the Atlantic Forest are 1) limited by the Doce and São Francisco rivers or 2) associated with the bioclimatically different southern and northeastern regions. We catalogued lists of forest birds from 45 locations, 36 in the Atlantic forest and nine in Amazon, and used parsimony analysis of endemicity to identify groups of shared taxa. We also compared differences between these groups by permutational multivariate analysis of variance and identified the species that best supported the resulting groups. The results showed that the distribution of forest birds is divided into two main regions in the Atlantic Forest, the first with more southern localities and the second with northeastern localities. This distributional pattern is not delimited by riverbanks, but it may be associated with bioclimatic units, surrogated by altitude, that maintain current environmental differences between two main regions on Atlantic Forest and may be related to phylogenetic histories of taxa supporting the two groups.

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.

Bivalve aquaculture transfers in Atlantic Europe. Part B: Environmental impacts of transfer activities

DEFF Research Database (Denmark)

Brenner, M.; Fraser, D.; Van Nieuwenhove, K.

2014-01-01

For centuries human populations have moved live shellfish around the world for consumption or aquaculture purposes; being relayed from their area of origin for growout or sale. This is in contrast to the inadvertent anthropogenic spreading of species via e.g. ballast waters. There are inherent...... designed to minimise the impact on ecosystems worldwide. In a companion paper details of actual transfer activities in Atlantic Europe are presented and all levels of legislation dealing with transfer activities on a global, regional and national scale are carefully reviewed....

A mid-Pleistocene rainforest corridor enabled synchronous invasions of the Atlantic Forest by Amazonian anole lizards.

Science.gov (United States)

Prates, Ivan; Rivera, Danielle; Rodrigues, Miguel T; Carnaval, Ana C

2016-10-01

Shifts in the geographic distribution of habitats over time can promote dispersal and vicariance, thereby influencing large-scale biogeographic patterns and ecological processes. An example is that of transient corridors of suitable habitat across disjunct but ecologically similar regions, which have been associated with climate change over time. Such connections likely played a role in the assembly of tropical communities, especially within the highly diverse Amazonian and Atlantic rainforests of South America. Although these forests are presently separated by open and dry ecosystems, paleoclimatic and phylogenetic evidence suggest that they have been transiently connected in the past. However, little is known about the timing, magnitude and the distribution of former forest connections. We employ sequence data at multiple loci from three codistributed arboreal lizards (Anolis punctatus, Anolis ortonii and Polychrus marmoratus) to infer the phylogenetic relationships among Amazonian and Atlantic Forest populations and to test alternative historical demographic scenarios of colonization and vicariance using coalescent simulations and approximate Bayesian computation (ABC). Data from the better-sampled Anolis species support colonization of the Atlantic Forest from eastern Amazonia. Hierarchical ABC indicates that the three species colonized the Atlantic Forest synchronously during the mid-Pleistocene. We find support of population bottlenecks associated with founder events in the two Anolis, but not in P. marmoratus, consistently with their distinct ecological tolerances. Our findings support that climatic fluctuations provided key opportunities for dispersal and forest colonization in eastern South America through the cessation of environmental barriers. Evidence of species-specific histories strengthens assertions that biological attributes play a role in responses to shared environmental change. © 2016 John Wiley & Sons Ltd.

Chemical and structural composition of Atlantic Canadian moose (Alces alces) incisors with patterns of high breakage

Energy Technology Data Exchange (ETDEWEB)

MacKenzie, Cynthia S. Kendall; Clough, Michael J. [Biology Department, Saint Mary' s University, Halifax, Nova Scotia, Canada B3H 3C3 (Canada); Broders, Hugh G., E-mail: hugh.broders@smu.ca [Biology Department, Saint Mary' s University, Halifax, Nova Scotia, Canada B3H 3C3 (Canada); Tubrett, Mike [Inco Innovation Centre, ICP-MS Facility, Memorial University of Newfoundland, P.O. Box 4200, St. John' s, Newfoundland, Canada A1C 5S7 (Canada)

2011-11-15

Analysis of mammalian teeth can provide information regarding local environmental conditions. For example, a high incidence of breakage and wear within a population may indicate poor food quality. Individuals consuming a diet causing high mechanical stress on their teeth, and/or lacking the appropriate minerals for proper development, could experience degradation of tooth condition. Previously, we documented a high rate of incisor tooth breakage, with age, in two genetically distinct moose populations in Atlantic Canada. In this study, multi-element ({sup 11}B, {sup 63}Cu, {sup 64}Zn, {sup 75}As, {sup 85}Rb, {sup 88}Sr, {sup 111}Cd, {sup 118}Sn, {sup 137}Ba, {sup 208}Pb, {sup 232}Th, and {sup 238}U) analyses using laser ablation ICP-MS were performed on moose incisors from multiple North American regions. The purpose was to determine whether the elemental composition of moose incisors varies among regions, and whether that variation is related to tooth degradation among Atlantic Canadian populations. A principal components analysis revealed that nearly 50% of the elemental variation in the inner enamel matrix of moose teeth was explained by three groupings of elements. The element groupings revealed differences among geographic regions, but did not explain the variation between incisors that were broken and those that were not. Regression models indicate that the elemental group which includes Cu, Pb, and Zn is related to decreases in incisal integrity. It is likely that other environmental factors contribute to the occurrence of increased incisor breakage in affected populations. The relationship between food resource quantity and quality, as a function of moose density, is hypothesized to explain loss of tooth integrity. - Highlights: {yields} Multi-element analysis of 1300 moose incisors using laser ablation ICP-MS. {yields} Three element groupings explain 50% of tooth composition variation among regions. {yields} Regional differences in tooth composition

The ability of general circulation models to simulate tropical cyclones and their precursors over the North Atlantic main development region

Energy Technology Data Exchange (ETDEWEB)

Daloz, Anne Sophie; Chauvin, Fabrice [Groupe de Modelisation Grande Echelle et Climat, CNRM-GAME, Meteo-France, Toulouse Cedex 1 (France); Walsh, Kevin [University of Melbourne, School of Earth Sciences, Melbourne, VIC (Australia); Lavender, Sally; Abbs, Deborah [CSIRO Atmospheric and Marine Research, Aspendale, VIC (Australia); Roux, Frank [Universite de Toulouse and Centre National de la Recherche Scientifique, Laboratoire d' Aerologie, Toulouse (France)

2012-10-15

The ability of General Circulation Models (GCMs) to generate Tropical Cyclones (TCs) over the North Atlantic Main Development Region (MDR; 10-20 N, 20-80 W; Goldenberg and Shapiro in J Clim 9:1169-1187, 1996) is examined through a subset of ocean-atmosphere coupled simulations from the World Climate Research Programme (WCRP) Coupled Model Intercomparison Project phase 3 (CMIP3) multimodel data set and a high-resolution (0.5 ) Sea Surface Temperature (SST)-forced simulation from the Australian Conformal-Cubic Atmospheric Model GCM. The results are compared with National Center for Environmental Prediction (NCEP-2) and European Center for Medium Range Weather Forecasts Re-Analysis (ERA-40) reanalyses over a common period from 1980 to 1998. Important biases in the representation of the TC activity are encountered over the MDR. This study emphasizes the strong link in the GCMs between African Easterly Waves (AEWs) and TC activity in this region. However, the generation of AEWs is not a sufficient condition alone for the models to produce TCs. Precipitation over the Sahel, especially rainfall over the Fouta Djallon highlands (cf. Fig. 1), is playing a role in the generation of TCs over the MDR. The influence of large-scale fields such as SST, vertical wind shear and tropospheric humidity on TC genesis is also examined. The ability of TC genesis indices, such as the Genesis Potential Index and the Convective Yearly Genesis Potential, to represent TC activity over the MDR in simulations at low to high spatial resolutions is analysed. These indices are found to be a reasonable method for comparing cyclogenesis in different models, even though other factors such as AEW activity should also be considered. (orig.)

2014 Mid-Atlantic Telehealth Resource Center Annual Summit

Directory of Open Access Journals (Sweden)

Katharine Hsu Wibberly

2013-12-01

Full Text Available The Mid-Atlantic Resource Center (MATRC; http://www.matrc.org/ advances the adoption and utilization of telehealth within the MATRC region and works collaboratively with the other federally funded Telehealth Resource Centers to accomplish the same nationally. MATRC offers technical assistance and other resources within the following mid-Atlantic states: Delaware, District of Columbia, Kentucky, Maryland, North Carolina, Pennsylvania, Virginia and West Virginia.   The 2014 MATRC Summit “Adding Value through Sustainable Telehealth” will be held March 30-April 1, 2014, at the Fredericksburg Expo & Conference Center, Fredericksburg, VA. The Summit will explore how telehealth adds value to patients, practitioners, hospitals, health systems, and other facilities. Participants will experience a highly interactive program built around the case history of “Mr. Doe” as he progresses through the primary care, inpatient hospitalization, and post-discharge environments. The Summit will conclude with a session on financial and business models for providing sustainable telehealth services.   For further information and registration, visit: http://matrc.org/component/content/article/2-uncategorised/80-mid-atlantic-telehealth-resource-summit-2014    

Atlantic Ocean CARINA data: overview and salinity adjustments

Directory of Open Access Journals (Sweden)

T. Tanhua

2010-02-01

Full Text Available Water column data of carbon and carbon-relevant hydrographic and hydrochemical parameters from 188 previously non-publicly available cruise data sets in the Arctic Mediterranean Seas, Atlantic and Southern Ocean have been retrieved and merged into a new database: CARINA (CARbon dioxide IN the Atlantic Ocean. The data have gone through rigorous quality control procedures to assure the highest possible quality and consistency. The data for the pertinent parameters in the CARINA database were objectively examined in order to quantify systematic differences in the reported values, i.e. secondary quality control. Systematic biases found in the data have been corrected in the three data products: merged data files with measured, calculated and interpolated data for each of the three CARINA regions, i.e. the Arctic Mediterranean Seas, the Atlantic and the Southern Ocean. These products have been corrected to be internally consistent. Ninety-eight of the cruises in the CARINA database were conducted in the Atlantic Ocean, defined here as the region south of the Greenland-Iceland-Scotland Ridge and north of about 30° S. Here we present an overview of the Atlantic Ocean synthesis of the CARINA data and the adjustments that were applied to the data product. We also report the details of the secondary QC (Quality Control for salinity for this data set. Procedures of quality control – including crossover analysis between stations and inversion analysis of all crossover data – are briefly described. Adjustments to salinity measurements were applied to the data from 10 cruises in the Atlantic Ocean region. Based on our analysis we estimate the internal consistency of the CARINA-ATL salinity data to be 4.1 ppm. With these adjustments the CARINA data products are consistent both internally as well as with GLODAP data, an oceanographic data set based on the World Hydrographic Program in the 1990s, and is now suitable for accurate assessments of, for example

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...

Atlantic Forest. A natural reservoir of chemical elements

International Nuclear Information System (INIS)

De Franca, E.J.; De Nadai Fernandes, E.A.; Bacchi, M.A.; Elias, C.

2008-01-01

The accumulation of chemical elements in biological compartments is one of the strategies of tropical species to adapt to a low-nutrient soil. This study focuses on the Atlantic Forest because of its eco-environmental importance as a natural reservoir of chemical elements. About 20 elements were determined by INAA in leaf, soil, litter and epiphyte compartments. There was no seasonality for chemical element concentrations in leaves, which probably indicated the maintenance of chemical elements in this compartment. Considering the estimated quantities, past deforestation events could have released large amounts of chemical elements to the environment. (author)

Future Changes in Cyclonic Wave Climate in the North Atlantic, with a Focus on the French West Indies

Science.gov (United States)

Belmadani, A.; Palany, P.; Dalphinet, A.; Pilon, R.; Chauvin, F.

2017-12-01

Tropical cyclones (TCs) are a major environmental hazard in numerous small islands such as the French West Indies (Guadeloupe, Martinique, St-Martin, St-Barthélémy). The intense associated winds, which can reach 300 km/h or more, can cause serious damage in the islands and their coastlines. In particular, the combined action of waves, currents and low atmospheric pressure leads to severe storm surge and coastal flooding. Here we report on future changes in cyclonic wave climate for the North Atlantic basin, as a preliminary step for downscaled projections over the French West Indies at sub-kilometer-scale resolution. A new configuration of the Météo-France ARPEGE atmospheric general circulation model on a stretched grid with increased resolution in the tropical North Atlantic ( 15 km) is able to reproduce the observed distribution of maximum surface winds, including extreme events corresponding to Category 5 hurricanes. Ensemble historical simulations (1985-2014, 5 members) and future projections with the IPCC (Intergovernmental Panel on Climate Change) RCP8.5 scenario (2051-2080, 5 members) are used to drive the MFWAM (Météo-France Wave Action Model) over the North Atlantic basin. A lower 50-km resolution grid is used to propagate distant mid-latitude swells into a higher 10-km resolution grid over the cyclonic basin. Wave model performance is evaluated over a few TC case studies including the Sep-Oct 2016 Category 5 Hurricane Matthew, using an operational version of ARPEGE at similar resolution to force MFWAM together with wave buoy data. The latter are also used to compute multi-year wave statistics, which then allow assessing the realism of the MFWAM historical runs. For each climate scenario and ensemble member, a simulation of the cyclonic season (July to mid-November) is performed every year. The simulated sea states over the North Atlantic cyclonic basin over 150 historical simulations are compared to their counterparts over 150 future simulations

Decadal-scale teleconnection between South Atlantic SST and southeast Australia surface air temperature in austral summer

Science.gov (United States)

Xue, Jiaqing; Li, Jianping; Sun, Cheng; Zhao, Sen; Mao, Jiangyu; Dong, Di; Li, Yanjie; Feng, Juan

2018-04-01

Austral summer (December-February) surface air temperature over southeast Australia (SEA) is found to be remotely influenced by sea surface temperature (SST) in the South Atlantic at decadal time scales. In austral summer, warm SST anomalies in the southwest South Atlantic induce concurrent above-normal surface air temperature over SEA. This decadal-scale teleconnection occurs through the eastward propagating South Atlantic-Australia (SAA) wave train triggered by SST anomalies in the southwest South Atlantic. The excitation of the SAA wave train is verified by forcing experiments based on both linear barotropic and baroclinic models, propagation pathway and spatial scale of the observed SAA wave train are further explained by the Rossby wave ray tracing analysis in non-uniform basic flow. The SAA wave train forced by southwest South Atlantic warming is characterized by an anomalous anticyclone off the eastern coast of the Australia. Temperature diagnostic analyses based on the thermodynamic equation suggest anomalous northerly flows on western flank of this anticyclone can induce low-level warm advection anomaly over SEA, which thus lead to the warming of surface air temperature there. Finally, SST-forced atmospheric general circulation model ensemble experiments also demonstrate that SST forcing in the South Atlantic is associated with the SAA teleconnection wave train in austral summer, this wave train then modulate surface air temperature over SEA on decadal timescales. Hence, observations combined with numerical simulations consistently demonstrate the decadal-scale teleconnection between South Atlantic SST and summertime surface air temperature over SEA.

Linking the South Atlantic Meridional Overturning Circulation and the Global Monsoons

Science.gov (United States)

Lopez, H.; Dong, S.; Goni, G. J.; Lee, S. K.

2016-02-01

This study tested the hypothesis whether low frequency decadal variability of the South Atlantic meridional heat transport (SAMHT) influences decadal variability of the global monsoons. A multi-century run from a state-of-the-art coupled general circulation model is used as basis for the analysis. Our findings indicate that multi-decadal variability of the South Atlantic Ocean plays a key role in modulating atmospheric circulation via interhemispheric changes in Atlantic Ocean heat content. Weaker SAMHT produces anomalous ocean heat divergence over the South Atlantic resulting in negative ocean heat content anomaly about 15 years later. This, in turn, forces a thermally direct anomalous interhemispheric Hadley circulation in the atmosphere, transporting heat from the northern hemisphere (NH) to the southern hemisphere (SH) and moisture from the SH to the NH, thereby intensify (weaken) summer (winter) monsoon in the NH and winter (summer) monsoon in the SH. Results also show that anomalous atmospheric eddies, both transient and stationary, transport heat northward in both hemispheres producing eddy heat flux convergence (divergence) in the NH (SH) around 15-30°, reinforcing the anomalous Hadley circulation. Overall, SAMHT decadal variability leads its atmospheric response by about 15 years, suggesting that the South Atlantic is a potential predictor of global climate variability.

Analyzing interaction of electricity markets and environmental policies using equilibrium models

Science.gov (United States)

Chen, Yihsu

Around the world, the electric sector is evolving from a system of regulated vertically-integrated monopolies to a complex system of competing generation companies, unregulated traders, and regulated transmission and distribution. One emerging challenge faced by environmental policymakers and electricity industry is the interaction between electricity markets and environmental policies. The objective of this dissertation is to examine these interactions using large-scale computational models of electricity markets based on noncooperative game theory. In particular, this dissertation is comprised of four essays. The first essay studies the interaction of the United States Environmental Protection Agency NOx Budget Program and the mid-Atlantic electricity market. This research quantifies emissions, economic inefficiencies, price distortions, and overall social welfare under various market assumptions using engineering-economic models. The models calculate equilibria for imperfectly competitive markets---Cournot oligopoly---considering the actual landscape of power plants and transmission lines, and including the possibility of market power in the NOx allowances market. The second essay extends the results from first essay and models imperfectly competitive markets using a Stackelberg or leader-follower formulation. A leader in the power and NO x markets is assumed to have perfect foresight of its rivals' responses. The rivals' best response functions are explicitly embedded in the leader's constraints. The solutions quantify the extent to which a leader in the markets can extract economic rents on the expense of its followers. The third essay investigates the effect of implementing the European Union (EU) CO2 Emissions Trading Scheme (ETS) on wholesale power prices in the Western European electricity market. This research uses theoretical and computational modeling approaches to quantify the degree to which CO2 costs were passed on to power prices, and quantifies the

Environmental radioactivity in the North Atlantic region including the Faroe Islands and Greenland

International Nuclear Information System (INIS)

Aarkrog, A.; Chen, Q.J.; Dahlgaard, H.; Hansen, H.; Nielsen, S.P.; Buch, E.; Christensen, G.C.; Holm, E.

1992-01-01

Measurements of fallout radioactivity in the North Atlantic region including the Faroe Islands and Greenland are reported. Strontium-90, cesium-137 and cesium-134 were 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 1988 and 1989. 99 Tc data on marine samples, in particular sea water from the Greenland Sea, are reported. (au) (91 taps., 51 ills., 7 refs.)

Dust Fertilization of the Western Atlantic Biota: a Biochemical Model

Science.gov (United States)

Holmes, C. W.

2017-12-01

Every year an estimated 50 million tons of African dust reaches the Western Atlantic. This dust is composed of quartz sand, clay, and a mixture of quartz and clay particles agglutinated with micronutrient enriched ferruginous cement. However, whether it is friend or foe to biochemical systems is a matter of conjecture. Corals are ideal recorders of changing conditions as the layers can be dated so that the record of chemical changes is easily assessed. There is extensive shallow-and deep water coral development bordering the Florida Straits. The changes in trace element chemistry within these corals show a positive relationship with the African dust record. Recently, it has been demonstrated that many of the metals contained within the dust are necessary micronutrients in the fertilization of plankton. Using the results of these studies, a biochemical model has been constructed. This model suggests a path from inorganic dust through microbial transformation to micronutrient enzymes (i.e. Cd-enriched carbonic anahydrase) and carbonate precipitation on the Bahamian Banks. It is estimated that more than ten million metric tons of this fine, metal-rich sediment is formed each year. However, for much of this sediment, its deposition is temporary, as it is transported into the Florida Straits yearly by tropical cyclones. This metal-enriched fine carbonate becomes nutrients for phytoplankton, providing food for the corals, both shallow and deep.

Otolith shape: a population marker for Atlantic herring Clupea harengus.

Science.gov (United States)

Libungan, L A; Óskarsson, G J; Slotte, A; Jacobsen, J A; Pálsson, S

2015-04-01

Otolith shape variation of seven Atlantic herring Clupea harengus populations from Canada, the Faroe Islands, Iceland, Ireland, Norway and Scotland, U.K., covering a large area of the species' distribution, was studied in order to see if otolith shape can be used to discriminate between populations. The otolith shape was obtained using quantitative shape analysis, transformed with Wavelet and analysed with multivariate methods. Significant differences were detected among the seven populations, which could be traced to three morphological structures in the otoliths. The differentiation in otolith shape between populations was not only correlated with their spawning time, indicating a strong environmental effect, but could also be due to differing life-history strategies. A model based on the shape differences discriminates with 94% accuracy between Icelandic summer spawners and Norwegian spring spawners, which are known to mix at feeding grounds. This study shows that otolith shape could become an accurate marker for C. harengus population discrimination. © 2015 The Fisheries Society of the British Isles.

Behavioural adaptations of two sympatric sandhoppers living on a mesotidal European Atlantic sandy beach

Science.gov (United States)

Bessa, Filipa; Marques, João Carlos; Scapini, Felicita

2014-06-01

Behavioural adaptations of supralittoral species on sandy beaches are expressed as responses to environmental changes and constitute a key factor in their survival and evolution. Two sympatric talitrid amphipods (Talitrus saltator and Britorchestia brito) from a mesotidal exposed sandy beach on the European Atlantic coast (Portugal) were compared as regards orientation and littoral zonation patterns under natural conditions. Orientation experiments were carried out during spring and summer 2011 and 2012 at Quiaios beach, a highly dynamic exposed sandy beach. Multiple regression models were fitted to the angular data and the environmental effects on orientation were investigated for each species. Both talitrids were shown to be well orientated towards the shoreline and finely adapted to the mesotidal environment but a different use of local cues and climatic features between the two species was apparent. T. saltator showed a lower precision in the orientation performance (with a bimodal distribution sea- and land-wards), with less dependence on the sun cues and higher dependence on climatic features. In addition, the zonation of T. saltator was across the land-sea axis during both seasons. For B. brito the landscape vision, sun visibility and the tidal range enhanced the orientation to the shoreline. On this mesotidal Atlantic beach, T. saltator appeared to have a more flexible orientation with respect to B. brito, which appeared to be more dependent on the conditions offered by the intertidal zone, a behaviour confirmed by its restricted zonation below the high tide mark. Consequently, T. saltator showed a more flexible behaviour that may be considered an important evolutionary adaptation to dynamic and mesotidal sandy beaches.

Predicting People's Environmental Behaviour: Theory of Planned Behaviour and Model of Responsible Environmental Behaviour

Science.gov (United States)

Chao, Yu-Long

2012-01-01

Using different measures of self-reported and other-reported environmental behaviour (EB), two important theoretical models explaining EB--Hines, Hungerford and Tomera's model of responsible environmental behaviour (REB) and Ajzen's theory of planned behaviour (TPB)--were compared regarding the fit between model and data, predictive ability,…

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.

Modelling environmental dynamics. Advances in goematic solutions

Energy Technology Data Exchange (ETDEWEB)

Paegelow, Martin [Toulouse-2 Univ., 31 (France). GEODE UMR 5602 CNRS; Camacho Olmedo, Maria Teresa (eds.) [Granada Univ (Spain). Dpto. de Analisis Geografico Regional y Geografia Fisica

2008-07-01

Modelling environmental dynamics is critical to understanding and predicting the evolution of the environment in response to the large number of influences including urbanisation, climate change and deforestation. Simulation and modelling provide support for decision making in environmental management. The first chapter introduces terminology and provides an overview of methodological modelling approaches which may be applied to environmental and complex dynamics. Based on this introduction this book illustrates various models applied to a large variety of themes: deforestation in tropical regions, fire risk, natural reforestation in European mountains, agriculture, biodiversity, urbanism, climate change and land management for decision support, etc. These case studies, provided by a large international spectrum of researchers and presented in a uniform structure, focus particularly on methods and model validation so that this book is not only aimed at researchers and graduates but also at professionals. (orig.)

Improving National Capability in Biogeochemical Flux Modelling: the UK Environmental Virtual Observatory (EVOp)

Science.gov (United States)

Johnes, P.; Greene, S.; Freer, J. E.; Bloomfield, J.; Macleod, K.; Reaney, S. M.; Odoni, N. A.

2012-12-01

The best outcomes from watershed management arise where policy and mitigation efforts are underpinned by strong science evidence, but there are major resourcing problems associated with the scale of monitoring needed to effectively characterise the sources rates and impacts of nutrient enrichment nationally. The challenge is to increase national capability in predictive modelling of nutrient flux to waters, securing an effective mechanism for transferring knowledge and management tools from data-rich to data-poor regions. The inadequacy of existing tools and approaches to address these challenges provided the motivation for the Environmental Virtual Observatory programme (EVOp), an innovation from the UK Natural Environment Research Council (NERC). EVOp is exploring the use of a cloud-based infrastructure in catchment science, developing an exemplar to explore N and P fluxes to inland and coastal waters in the UK from grid to catchment and national scale. EVOp is bringing together for the first time national data sets, models and uncertainty analysis into cloud computing environments to explore and benchmark current predictive capability for national scale biogeochemical modelling. The objective is to develop national biogeochemical modelling capability, capitalising on extensive national investment in the development of science understanding and modelling tools to support integrated catchment management, and supporting knowledge transfer from data rich to data poor regions, The AERC export coefficient model (Johnes et al., 2007) has been adapted to function within the EVOp cloud environment, and on a geoclimatic basis, using a range of high resolution, geo-referenced digital datasets as an initial demonstration of the enhanced national capacity for N and P flux modelling using cloud computing infrastructure. Geoclimatic regions are landscape units displaying homogenous or quasi-homogenous functional behaviour in terms of process controls on N and P cycling

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.

Millennial-scale variations in dustiness recorded in Mid-Atlantic sediments from 0 to 70 ka

Science.gov (United States)

Middleton, Jennifer L.; Mukhopadhyay, Sujoy; Langmuir, Charles H.; McManus, Jerry F.; Huybers, Peter J.

2018-01-01

Sedimentary records of dust deposition in the subtropical Atlantic provide important constraints on millennial- and orbital-scale variability in atmospheric circulation and North African aridity. Constant flux proxies, such as extraterrestrial helium-3, yield dust flux records that are independent of the biases caused by lateral sediment transport and limited resolution that may be associated with age-model-derived mass accumulation rates. However, Atlantic dust records constrained using constant flux proxies are sparsely distributed and generally limited to the past 20 ka. Here we extend the Atlantic record of North African dust deposition to 70 ka using extraterrestrial helium-3 and measurements of titanium, thorium, and terrigenous helium-4 in two sediment cores collected at 26°N and 29°N on the Mid-Atlantic Ridge and compare results to model estimates for dust deposition in the subtropical North Atlantic. Dust proxy fluxes between 26°N and 29°N are well correlated, despite variability in lateral sediment transport, and underscore the utility of extraterrestrial helium-3 for constraining millennial-scale variability in dust deposition. Similarities between Mid-Atlantic dust flux trends and those observed along the Northwest African margin corroborate previous interpretations of dust flux variability over the past 20 ka and suggest that long distance transport and depositional processes do not overly obscure the signal of North African dust emissions. The 70 ka Mid-Atlantic record reveals a slight increase in North African dustiness from Marine Isotope Stage 4 through the Last Glacial Maximum and a dramatic decrease in dustiness associated with the African Humid Period. On the millennial-scale, the new records exhibit brief dust maxima coincident with North Atlantic cold periods such as the Younger Dryas, and multiple Heinrich Stadials. The correlation between Mid-Atlantic dust fluxes and previous constraints on North African aridity is high. However

75 FR 41163 - Notice of Intent To Prepare an Environmental Impact Statement and Overseas Environmental Impact...

Science.gov (United States)

2010-07-15

...Pursuant to section 102 of the National Environmental Policy Act (NEPA) of 1969, as implemented by the Council on Environmental Quality Regulations (40 Code of Federal Regulations [CFR] Parts 1500- 1508), and Executive Order 12114, the Department of the Navy (DON) announces its intent to prepare an Environmental Impact Statement (EIS) and Overseas EIS (OEIS) to evaluate the potential environmental effects associated with military readiness training and research, development, testing, and evaluation (RDT&E) activities (hereinafter referred to as ``training and testing'' activities) conducted within the Atlantic Fleet Training and Testing (AFTT) study area. The AFTT study area includes the western North Atlantic Ocean along the east coast of North America (including the area where the Undersea Warfare Training Range will be used), the Chesapeake Bay, and the Gulf of Mexico. Also included are select Navy pierside locations and channels. The AFTT study area does not include the Arctic. This EIS and OEIS is being prepared to renew and combine current regulatory permits and authorizations; address current training and testing not covered under existing permits and authorizations; and to obtain those permits and authorizations necessary to support force structure changes and emerging and future training and testing requirements. The DON will invite the National Marine Fisheries Service to be a cooperating agency in preparation of this EIS and OEIS.

77 FR 35357 - Atlantic Highly Migratory Species; Commercial Atlantic Region Non-Sandbar Large Coastal Shark...

Science.gov (United States)

2012-06-13

... Highly Migratory Species; Commercial Atlantic Region Non-Sandbar Large Coastal Shark Fishery Opening Date... commercial Atlantic region non-sandbar large coastal shark fishery. This action is necessary to inform... large coastal shark fishery will open on July 15, 2012. FOR FURTHER INFORMATION CONTACT: Karyl Brewster...

Appendix D of the Final Report of the Mid-Atlantic Marine Wildlife Surveys, Modeling, and Data. Workshop to Establish Coordination and Communication

Energy Technology Data Exchange (ETDEWEB)

None

2013-07-01

The Wind Program hosted a two-day workshop on July 24-25, 2012 with scientists and regulators engaged in marine ecological survey, modeling, and database efforts pertaining to the waters of the Mid-Atlantic region. This is the fourth appendix to the report, the presentations from the workshop.

A software engineering perspective on environmental modeling framework design: The object modeling system

Science.gov (United States)

The environmental modeling community has historically been concerned with the proliferation of models and the effort associated with collective model development tasks (e.g., code generation, data provisioning and transformation, etc.). Environmental modeling frameworks (EMFs) have been developed to...

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.

Mechanisms of meridional transport processes in the tropical Atlantic; Mechanismen meridionaler Transportprozesse im tropischen Atlantik

Energy Technology Data Exchange (ETDEWEB)

Kroeger, J.

2001-07-01

Meridional transport processes of water masses and tracers in the subtropical and tropical Atlantic are investigated using a regional eddy resolving model of the wind driven and thermohaline circulation. Analytical emphasis is on float simulations in the model which, complementary to Eulerian means, represent the Lagrangian view and give further insight into the spreading and pathways of characteristic water masses in this area. In the tropics and subtropics shallow 3-dimensional circulation cells are superimposed on the northward warm water transfer within the deep reaching thermohaline overturning cell (MOC) as part of the global ''Conveyor Belt''. Under present-day climate conditions the model shows that the equatorial thermocline is exclusively ventilated by subsurface flow within the tropical-subtropical cell (STC) of the South Atlantic. Only with a prescribed ''Conveyor-off''-Mode the STC of the North Atlantic contributes to this ventilation process with equal amounts. Throughout the year the interhemispheric transport of surface and central water masses of South Atlantic origin into the Caribbean Sea is dominated by zonal detours to the east as a consequence of the interplay of several retroflection events occuring in the North Atlantic. The eulerian mean flow field in the deep layer postulates the interhemispheric mass transport into the South Atlantic to be confined entirely to the western boundary, whereas Lagrangian means indicate intermittent eastward excursions along the equator, related to seasonally alternating zonal currents due to long Rossby waves. It was suggested that the observed characteristic eastward maximum of tracer concentrations along the equator is a consequence of rectifying effects of single or interacting equatorial waves. The model does not validate this hypothesis. The response to transport anomalies of subpolar origin and long periodicity is subject to different time-scales in both

77 FR 50672 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Snapper-Grouper Fishery Off the...

Science.gov (United States)

2012-08-22

... National Environmental Policy Act, including biological, economic, social, administrative, and cumulative... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 622 RIN 0648-BC30 Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Snapper-Grouper Fishery Off the...

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.

Atlantic Bluefin Tuna (Thunnus thynnus) Biometrics and Condition.

Science.gov (United States)

Rodriguez-Marin, Enrique; Ortiz, Mauricio; Ortiz de Urbina, José María; Quelle, Pablo; Walter, John; Abid, Noureddine; Addis, Piero; Alot, Enrique; Andrushchenko, Irene; Deguara, Simeon; Di Natale, Antonio; Gatt, Mark; Golet, Walter; Karakulak, Saadet; Kimoto, Ai; Macias, David; Saber, Samar; Santos, Miguel Neves; Zarrad, Rafik

2015-01-01

The compiled data for this study represents the first Atlantic and Mediterranean-wide effort to pool all available biometric data for Atlantic bluefin tuna (Thunnus thynnus) with the collaboration of many countries and scientific groups. Biometric relationships were based on an extensive sampling (over 140,000 fish sampled), covering most of the fishing areas for this species in the North Atlantic Ocean and Mediterranean Sea. Sensitivity analyses were carried out to evaluate the representativeness of sampling and explore the most adequate procedure to fit the weight-length relationship (WLR). The selected model for the WLRs by stock included standardized data series (common measurement types) weighted by the inverse variability. There was little difference between annual stock-specific round weight-straight fork length relationships, with an overall difference of 6% in weight. The predicted weight by month was estimated as an additional component in the exponent of the weight-length function. The analyses of monthly variations of fish condition by stock, maturity state and geographic area reflect annual cycles of spawning and feeding behavior. We update and improve upon the biometric relationships for bluefin currently used by the International Commission for the Conservation of Atlantic Tunas, by incorporating substantially larger datasets than ever previously compiled, providing complete documentation of sources and employing robust statistical fitting. WLRs and other conversion factors estimated in this study differ from the ones used in previous bluefin stock assessments.

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.

From promise to crisis : lessons for Atlantic Canada from Ontario's electricity liberalisation

International Nuclear Information System (INIS)

Adams, T.

2000-01-01

This report synthesized some lessons learned from Ontario's electric power restructuring and showed how they can be applied to reform the Atlantic Canada's electricity sector. Since the opening of Ontario electricity markets to competition, numerous problems have threatened the potential of the power sector to deliver reasonably priced, reliable and environmentally responsible electricity to consumers in Ontario. The original vision of power restructuring in Ontario called for the break-up of Ontario Hydro, the privatisation of major components of the power system, major regulatory improvements, more stringent environmental rules, the creation of an independent agency responsible for power system reliability, and the opening of electricity markets to competition. This original vision has failed for many reasons, including failure to establish a firm date for the opening of the electricity market, a lack of financial accountability, continued subsidies to industrial customers, local distribution rate shock, lack of investment, politicizing transmission tariffs, aggressive marketers exploiting consumer uncertainty and ill-advised deregulation of fossil emissions. It was emphasized that Atlantic Canada could benefit from any eventual electricity restructuring by avoiding these mistakes made in Ontario. This report also described the contents of an 8 point program that was recommended by the author. 21 refs

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.)

76 FR 37788 - Fisheries of the South Atlantic; South Atlantic Fishery Management Council; Public Meeting

Science.gov (United States)

2011-06-28

... meeting of its Law Enforcement AP in Orlando, FL. DATES: The meeting will take place July 20, 2011. See SUPPLEMENTARY INFORMATION. ADDRESSES: The meeting will be held at the Marriott Renaissance Orlando Hotel, 5445... the South Atlantic; South Atlantic Fishery Management Council; Public Meeting AGENCY: National Marine...

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.

Predation on Pacific salmonid eggs and carcass's by subyearling Atlantic salmon in a tributary of Lake Ontario

Science.gov (United States)

Johnson, James H.; Chalupnicki, Marc A.; Abbett, Ross; Verdoliva, Francis

2016-01-01

A binational effort to reintroduce Atlantic salmon (Salmo salar) that were extirpated in the Lake Ontario ecosystem for over a century is currently being undertaken by the New York State Department of Environmental Conservation and the Ontario Ministry of Natural Resources. Reintroduction actions include the release of several life stages including fry, fall fingerlings, and yearling smolts. In this study we describe the diet of recently released fall fingerling Atlantic salmon in a tributary of the Salmon River, New York. A specific objective of the study was to determine if juvenile Atlantic salmon would utilize the high caloric food source provided by introduced Pacific salmonids (Oncorhynchus spp.) that includes eggs and carcass flesh. Salmon eggs and carcass flesh comprised 20.5% of the October to January diet in 2013–14 and 23.9% in 2014–15. The consumption of steelhead (O. mykiss) eggs was a major part of the diet in April in both 2014 (54.1%) and 2015 (33.2%). This study documented that recently released Atlantic salmon will consume the high caloric food material provided by Pacific salmonids and that the consumption of this material extends for several months.

Aerosol-Radiation-Cloud Interactions in the South-East Atlantic: Future Suborbital Activities to Address Knowledge Gaps in Satellite and Model Assessments

Science.gov (United States)

Redemann, Jens; Wood, R.; Zuidema, P.; Haywood, J.; Piketh, S.; Formenti, P.; L'Ecuyer, T.; Kacenelenbogen, M.; Segal-Rosenheimer, M.; Shinozuka, Y.;

Interannual-to-decadal air-sea interactions in the tropical Atlantic region

Science.gov (United States)

Ruiz-Barradas, Alfredo

2001-09-01

The present research identifies modes of atmosphere-ocean interaction in the tropical Atlantic region and the mechanisms by which air-sea interactions influence the regional climate. Novelties of the present work are (1)the use of relevant ocean and atmosphere variables important to identity coupled variability in the system. (2)The use of new data sets, including realistic diabatic heating. (3)The study of interactions between ocean and atmosphere relevant at interannual-to-decadal time scales. Two tropical modes of variability are identified during the period 1958-1993, the Atlantic Niño mode and the Interhemispheric mode. Those modes have defined structures in both ocean and atmosphere. Anomalous sea surface temperatures and winds are associated to anomalous placement of the Intertropical Convergence Zone (ITCZ). They develop maximum amplitude during boreal summer and spring, respectively. The anomalous positioning of the ITCZ produces anomalous precipitation in some places like Nordeste, Brazil and the Caribbean region. Through the use of a diagnostic primitive equation model, it is found that the most important terms controlling local anomalous surface winds over the ocean are boundary layer temperature gradients and diabatic heating anomalies at low levels (below 780 mb). The latter is of particular importance in the deep tropics in producing the anomalous meridional response to the surface circulation. Simulated latent heat anomalies indicate that a thermodynamic feedback establishes positive feedbacks at both sides of the equator and west of 20°W in the deep tropics and a negative feedback in front of the north west coast of Africa for the Interhemispheric mode. This thermodynamic feedback only establishes negative feedbacks for the Atlantic Niño mode. Transients establish some connection between the tropical Atlantic and other basins. Interhemispheric gradients of surface temperature in the tropical Atlantic influence winds in the midlatitude North

Report of the independent review of disposal of radioactive waste in the northeast Atlantic

International Nuclear Information System (INIS)

Holliday, F.G.T.; Clark, R.

1984-01-01

This report reviews the scientific evidence, including the environmental implications, relevant to the safety of disposal of radioactive waste at 'the designated North Atlantic site'. It falls under the headings: aims and background; the nature of the problem (what is pollution; what is radiation; radioactive half-life; radioactivity in the sea; hazards of radioactivity; transfer mechanisms from sea to man; standards for radiation exposure to man); past and present practices (the London Dumping Convention; the OECD mechanism; sources and composition of the waste; structure of responsibility; authorisation; practical arrangements; packaging; present practices by other countries); the oceanography of the dump site (location; topography; biology; currents and water circulation; dilution and adsorption on to sediments); estimation of doses (why modelling; modelling techniques; the waste package model; models of dispersion in the ocean; a box model of ocean dispersion; a model of transfer through a food chain; dose assessment); alternatives (land-based alternatives; sea-based alternatives; storage); discussion (reliability of assessment; public acceptability of perceived risk; collective doses); conclusions (hazard to health; present scientific evidence; future dumping; storage; future research and monitoring; public and social factors; buoyant materials); recommendations. (U.K.)

El Niño, Sea Surface Temperature Anomaly and Coral Bleaching in the South Atlantic: A Chain of Events Modeled With a Bayesian Approach

Science.gov (United States)

Lisboa, D. S.; Kikuchi, R. K. P.; Leão, Zelinda M. A. N.

2018-04-01

Coral bleaching represents one of the main climate-change related threats to reef ecosystems. This research represents a methodological alternative for modeling this phenomenon, focused on assessing uncertainties and complexities with a low number of observations. To develop this model, intermittent reef monitoring data from the largest reef complex in the South Atlantic collected over nine summers between 2000 and 2014 were used with remote sensing data to construct and train a bleaching seasonal prediction model. The Bayesian approach was used to construct the network as it is suitable for hierarchically organizing local thermal variables and combining them with El Niño indicators from the preceding winter to generate accurate bleaching predictions for the coming season. Network count information from six environmental indicators was used to calculate the probability of bleaching, which is mainly influenced by the combined information of two thermal indices; one thermal index is designed to track short period anomalies in the early summer that are capable of triggering bleaching (SST of five consecutive days), and the other index is responsible for tracking the accumulation of thermal stress over time, an index called degree heating trimester (DHT). In addition to developing the network, this study conducted the three tests of applicability proposed for model: 1- Perform the forecast of coral bleaching for the summer of 2016; 2- Investigate the role of turbidity during the bleaching episodes; and 3- Use the model information to identify areas with a lower predisposition to bleaching events.

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.

A Knowledge-Based Representation Scheme for Environmental Science Models

Science.gov (United States)

Keller, Richard M.; Dungan, Jennifer L.; Lum, Henry, Jr. (Technical Monitor)

1994-01-01

One of the primary methods available for studying environmental phenomena is the construction and analysis of computational models. We have been studying how artificial intelligence techniques can be applied to assist in the development and use of environmental science models within the context of NASA-sponsored activities. We have identified several high-utility areas as potential targets for research and development: model development; data visualization, analysis, and interpretation; model publishing and reuse, training and education; and framing, posing, and answering questions. Central to progress on any of the above areas is a representation for environmental models that contains a great deal more information than is present in a traditional software implementation. In particular, a traditional software implementation is devoid of any semantic information that connects the code with the environmental context that forms the background for the modeling activity. Before we can build AI systems to assist in model development and usage, we must develop a representation for environmental models that adequately describes a model's semantics and explicitly represents the relationship between the code and the modeling task at hand. We have developed one such representation in conjunction with our work on the SIGMA (Scientists' Intelligent Graphical Modeling Assistant) environment. The key feature of the representation is that it provides a semantic grounding for the symbols in a set of modeling equations by linking those symbols to an explicit representation of the underlying environmental scenario.

Evaluating machine-learning techniques for recruitment forecasting of seven North East Atlantic fish species

KAUST Repository

Fernandes, José Antonio

2015-01-01

The effect of different factors (spawning biomass, environmental conditions) on recruitment is a subject of great importance in the management of fisheries, recovery plans and scenario exploration. In this study, recently proposed supervised classification techniques, tested by the machine-learning community, are applied to forecast the recruitment of seven fish species of North East Atlantic (anchovy, sardine, mackerel, horse mackerel, hake, blue whiting and albacore), using spawning, environmental and climatic data. In addition, the use of the probabilistic flexible naive Bayes classifier (FNBC) is proposed as modelling approach in order to reduce uncertainty for fisheries management purposes. Those improvements aim is to improve probability estimations of each possible outcome (low, medium and high recruitment) based in kernel density estimation, which is crucial for informed management decision making with high uncertainty. Finally, a comparison between goodness-of-fit and generalization power is provided, in order to assess the reliability of the final forecasting models. It is found that in most cases the proposed methodology provides useful information for management whereas the case of horse mackerel is an example of the limitations of the approach. The proposed improvements allow for a better probabilistic estimation of the different scenarios, i.e. to reduce the uncertainty in the provided forecasts.

Atlante project; Progetto atlante. Quadro di riferimento, analisi degli strumenti esistenti, implementazione metodologica e applicazione prototipale

Energy Technology Data Exchange (ETDEWEB)

Baratozzi, L.; Cagnoli, P.; Filippi, N.; Gherardi, L.; Montaletti, V.; Poli, G.; Scarelli, M. [Regione Emilia Romagna, Assessorato Territorio, Programmazione e Ambiente, Servizio Paesaggio, Parchi e Patrimonio Naturale, Bologna (Italy); Basili, M.; Battista, A.; Colonna, R.; Del Cellio, R.; Forni, A.; Olivetti, I.; Regina, P.; Zarlenga, F. [ENEA, Divisione Caratterizzazione dell' Ambiente e del Territorio, Centro Ricerche della Casaccia, S. Maria di Galeria, RM (Italy)

2001-07-01

This paper presents the Atlante project a joint program of Emilia Romagna region and Italian ENEA based on the concept of substantiality and the most important methods and models used in the territorial planning. [Italian] La redazione del presente volume e' stata articolata in modo da bilanciare, da un lato l'esigenza di rispettare il programma di attivita' previsto nell'ambito della Convenzione fra Regione Emilia Romagna ed ENEA.

Knowledge-Based Environmental Context Modeling

Science.gov (United States)

Pukite, P. R.; Challou, D. J.

2017-12-01

As we move from the oil-age to an energy infrastructure based on renewables, the need arises for new educational tools to support the analysis of geophysical phenomena and their behavior and properties. Our objective is to present models of these phenomena to make them amenable for incorporation into more comprehensive analysis contexts. Starting at the level of a college-level computer science course, the intent is to keep the models tractable and therefore practical for student use. Based on research performed via an open-source investigation managed by DARPA and funded by the Department of Interior [1], we have adapted a variety of physics-based environmental models for a computer-science curriculum. The original research described a semantic web architecture based on patterns and logical archetypal building-blocks (see figure) well suited for a comprehensive environmental modeling framework. The patterns span a range of features that cover specific land, atmospheric and aquatic domains intended for engineering modeling within a virtual environment. The modeling engine contained within the server relied on knowledge-based inferencing capable of supporting formal terminology (through NASA JPL's Semantic Web for Earth and Environmental Technology (SWEET) ontology and a domain-specific language) and levels of abstraction via integrated reasoning modules. One of the key goals of the research was to simplify models that were ordinarily computationally intensive to keep them lightweight enough for interactive or virtual environment contexts. The breadth of the elements incorporated is well-suited for learning as the trend toward ontologies and applying semantic information is vital for advancing an open knowledge infrastructure. As examples of modeling, we have covered such geophysics topics as fossil-fuel depletion, wind statistics, tidal analysis, and terrain modeling, among others. Techniques from the world of computer science will be necessary to promote efficient

Developing an Event-Tree Probabilistic Tsunami Inundation Model for NE Atlantic Coasts: Application to a Case Study

Science.gov (United States)

Omira, R.; Matias, L.; Baptista, M. A.

2016-12-01

This study constitutes a preliminary assessment of probabilistic tsunami inundation in the NE Atlantic region. We developed an event-tree approach to calculate the likelihood of tsunami flood occurrence and exceedance of a specific near-shore wave height for a given exposure time. Only tsunamis of tectonic origin are considered here, taking into account local, regional, and far-field sources. The approach used here consists of an event-tree method that gathers probability models for seismic sources, tsunami numerical modeling, and statistical methods. It also includes a treatment of aleatoric uncertainties related to source location and tidal stage. Epistemic uncertainties are not addressed in this study. The methodology is applied to the coastal test-site of Sines located in the NE Atlantic coast of Portugal. We derive probabilistic high-resolution maximum wave amplitudes and flood distributions for the study test-site considering 100- and 500-year exposure times. We find that the probability that maximum wave amplitude exceeds 1 m somewhere along the Sines coasts reaches about 60 % for an exposure time of 100 years and is up to 97 % for an exposure time of 500 years. The probability of inundation occurrence (flow depth >0 m) varies between 10 % and 57 %, and from 20 % up to 95 % for 100- and 500-year exposure times, respectively. No validation has been performed here with historical tsunamis. This paper illustrates a methodology through a case study, which is not an operational assessment.

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

Comparison of in situ observations of air traffic emission signatures in the North Atlantic flight corridor with simulations using a Gaussian plume model

Energy Technology Data Exchange (ETDEWEB)

Konopka, P; Schlager, H; Schulte, P; Schumann, U; Ziereis, H [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere; Hagen, D; Whitefield, P [Missouri Univ., Rolla, MO (United States). Lab. for Cloud and Aerosol Science

1998-12-31

Focussed aircraft measurements including NO, NO{sub 2}, O{sub 3}, and aerosols (CN) have been carried out over the Eastern North Atlantic as part of the POLINAT (Pollution from Aircraft Emissions in the North Atlantic Flight Corridor) project to search for small and large scale signals of air traffic emissions in the corridor region. Here, the experimental data measured at cruising altitudes on November, 6, 1994 close to peak traffic hours are considered. Observed peak concentrations in small scale NO{sub x} spikes exceed background level of about 50 pptv by up to two orders of magnitude. The measured NO{sub x} concentration field is compared with simulations obtained with a plume dispersion model using collected air traffic data and wind measurements. Additionally, the measured and calculated NO/NO{sub x} ratios are considered. The comparison with the model shows that the observed (multiple-)peaks can be understood as a superposition of several aircraft plumes with ages up to 3 hours. (author) 12 refs.

Comparison of in situ observations of air traffic emission signatures in the North Atlantic flight corridor with simulations using a Gaussian plume model

Energy Technology Data Exchange (ETDEWEB)

Konopka, P.; Schlager, H.; Schulte, P.; Schumann, U.; Ziereis, H. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere; Hagen, D.; Whitefield, P. [Missouri Univ., Rolla, MO (United States). Lab. for Cloud and Aerosol Science

1997-12-31

Focussed aircraft measurements including NO, NO{sub 2}, O{sub 3}, and aerosols (CN) have been carried out over the Eastern North Atlantic as part of the POLINAT (Pollution from Aircraft Emissions in the North Atlantic Flight Corridor) project to search for small and large scale signals of air traffic emissions in the corridor region. Here, the experimental data measured at cruising altitudes on November, 6, 1994 close to peak traffic hours are considered. Observed peak concentrations in small scale NO{sub x} spikes exceed background level of about 50 pptv by up to two orders of magnitude. The measured NO{sub x} concentration field is compared with simulations obtained with a plume dispersion model using collected air traffic data and wind measurements. Additionally, the measured and calculated NO/NO{sub x} ratios are considered. The comparison with the model shows that the observed (multiple-)peaks can be understood as a superposition of several aircraft plumes with ages up to 3 hours. (author) 12 refs.

Modelling and forecasting long-term dynamics of Western Baltic macrobenthic fauna in relation to climate signals and environmental change

Science.gov (United States)

Gröger, Joachim; Rumohr, Heye

2006-05-01

Long-term macrobenthos data from Kiel Bight in the Western Baltic collected between 1968 and 2000 have been correlated with the winter NAO index (North Atlantic Oscillation Index) and other environmental data such as temperature, salinity and oxygen content in the bottom water in order to detect systematic patterns related to so far unexplained abiotic signals in the dynamics of zoobenthic species assemblages. The benthos data come from a cluster of five stations (Süderfahrt/ Millionenviertel) in Kiel Bay. Our investigations concentrated on the macrobenthic dynamics with a focus on the number of species m - 2 (species richness). Using logarithms and the time series analysis approach of Box/Jenkins (ARIMA modelling, transfer function modelling) it was shown that species richness was strongly influenced by the winter NAO (adjusted for a linear time trend within the 1968-2000 period) and salinity (with a shift/lag of four years). Bootstrapping experiments (i.e. sampling from the error process) and analysis of prediction power (by means of the one- or more-years leaving-out method) showed that the parameter estimates behaved in a stable way, leading to a relatively robust model.

Application of a predictive Bayesian model to environmental accounting.

Science.gov (United States)

Anex, R P; Englehardt, J D

2001-03-30

Environmental accounting techniques are intended to capture important environmental costs and benefits that are often overlooked in standard accounting practices. Environmental accounting methods themselves often ignore or inadequately represent large but highly uncertain environmental costs and costs conditioned by specific prior events. Use of a predictive Bayesian model is demonstrated for the assessment of such highly uncertain environmental and contingent costs. The predictive Bayesian approach presented generates probability distributions for the quantity of interest (rather than parameters thereof). A spreadsheet implementation of a previously proposed predictive Bayesian model, extended to represent contingent costs, is described and used to evaluate whether a firm should undertake an accelerated phase-out of its PCB containing transformers. Variability and uncertainty (due to lack of information) in transformer accident frequency and severity are assessed simultaneously using a combination of historical accident data, engineering model-based cost estimates, and subjective judgement. Model results are compared using several different risk measures. Use of the model for incorporation of environmental risk management into a company's overall risk management strategy is discussed.

Trace metals in corals--hind casting environmental chemical changes in the tropical Atlantic waters

Science.gov (United States)

Holmes, C. W.; Koenig, A.; Ridley, W. I.; Wilson, S. A.

2002-12-01

As corals grow, they secrete a calcareous skeleton with the aid of photosynthetic activity of endosymbiotic dinoflagellates (zooxanthellae). The rate of this secretion varies inter-annually. Entrapped with the carbonate are trace substances that record the chemistry of the surrounding ocean. Detailing changes in chemistry requires careful and very tedious high-resolution sampling. The advent of laser ablation inductive couple plasma/mass spectroscopy (LA-ICP/MS) circumvents this sampling problem. This method also permits a continuous scan of the entire coral skeleton. Another problem has been the lack of a carbonate standard which appears to be resolved with the creation of an artificial carbonate standard (USGS MAC-1). This standard is presently undergoing rigorous analysis, but preliminary results are very positive. The LA-ICP/MS data of three Atlantic corals reveals an intriguing distribution of trace metals and boron that may be related to climatic driven chemical changes during the last hundred years. The distribution of the trace metals appears to have an association with three climate signals: 1. the strength of the North Atlantic Oscillation (NAO), 2. the local effects of El Nino in the Florida region and 3. change in oceanic chemistry, possibly due to rising CO2. Aluminum and titanium levels vary with the strength of the NAO. The highest concentrations occur at the time of strong positive NOA when there is large amount of sediment transported off the deserts of North Africa. This relationship is particularly strong in the coral from the Cape Verde Islands. Along the eastern seaboard of the Atlantic, the relationship is not as pronounced but still observable. Nutrients and anthropogenic trace metals, such as zinc, lead, and mercury appear to correlate with local conditions and show a weak correspondence to the El Nino as it affects south Florida. Boron variation is directly related to the high-density bands of the corals. The long-term record of boron

Ecological and evolutionary patterns of freshwater maturation in Pacific and Atlantic salmonines

Science.gov (United States)

Sloat, Matthew R.; Fraser, Dylan J.; Dunham, Jason B.; Falke, Jeffery A.; Jordan, Chris E.; McMillan, John R.; Ohms, Haley A.

2014-01-01

Reproductive tactics and migratory strategies in Pacific and Atlantic salmonines are inextricably linked through the effects of migration (or lack thereof) on age and size at maturity. In this review, we focus on the ecological and evolutionary patterns of freshwater maturation in salmonines, a key process resulting in the diversification of their life histories. We demonstrate that the energetics of maturation and reproduction provides a unifying theme for understanding both the proximate and ultimate causes of variation in reproductive schedules among species, populations, and the sexes. We use probabilistic maturation reaction norms to illustrate how variation in individual condition, in terms of body size, growth rate, and lipid storage, influences the timing of maturation. This useful framework integrates both genetic and environmental contributions to conditional strategies for maturation and, in doing so, demonstrates how flexible life histories can be both heritable and subject to strong environmental influences. We review evidence that the propensity for freshwater maturation in partially anadromous species is predictable across environmental gradients at geographic and local spatial scales. We note that growth is commonly associated with the propensity for freshwater maturation, but that life-history responses to changes in growth caused by temperature may be strikingly different than changes caused by differences in food availability. We conclude by exploring how contemporary management actions can constrain or promote the diversity of maturation phenotypes in Pacific and Atlantic salmonines and caution against underestimating the role of freshwater maturing forms in maintaining the resiliency of these iconic species.

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...

Thermal Habitat Index of Many Northwest Atlantic Temperate Species Stays Neutral under Warming Projected for 2030 but Changes Radically by 2060

Czech Academy of Sciences Publication Activity Database

Shackell, N.L.; Ricard, Daniel; Stortini, C.

2014-01-01

Roč. 9, č. 3 (2014), e90662 E-ISSN 1932-6203 Institutional support: RVO:60077344 Keywords : climate change * environmental parameters * Atlantic Ocean * greenhouse effect Subject RIV: EH - Ecology, Behaviour Impact factor: 3.234, year: 2014

Environmental indicators and international models for making decision

International Nuclear Information System (INIS)

Polanco, Camilo

2006-01-01

The last international features proposed by the Organization for Economic Cooperation Development (OECD) and United Nations (UN) are analyzed in the use of the environmental indicators, in typology, selection criteria, and models, for organizing the information for management, environmental performance, and decision making. The advantages and disadvantages of each model are analyzed, as well as their environmental index characteristics. The analyzed models are Pressure - State - Response (PSR) and its conceptual developments: Driving Force - State Response (DSR), Driving Force - Pressure - State - Impact - Response (DPSIR), Model- Flow-Quality (MFQ), Pressure - State - Impact - Effect - Response (PSIER), and, finally, Pressure-State - Impact - Effect - Response - Management (PSIERM). The use of one or another model will depend on the quality of the available information, as well as on the proposed objectives

Atlantic energy and the strategic outlook

Directory of Open Access Journals (Sweden)

Paul Isbell

2013-09-01

Full Text Available Sweeping changes are beginning to transform energy scenarios around the world. The gas revolution, a renaissance in petroleum technology and exploration, and a chaotic but powerful movement toward the goal of low-carbon economies are three of the principal energy trends currently interacting with structural changes in the geo-economics of the Atlantic world to present new perspectives and opportunitiesfor the diverse actors in the ‘Atlantic Basin’. This article explores how changes in the energy landscape are contributing to a reassessment of the strategic horizon. The potential impacts of the shale revolution, deep-offshore oil, biofuels and other modern renewable energies on the geopolitics of the Atlantic Basin will be assessed, and the hypothesis that an Atlantic Basin energy system is now taking shape will be evaluated, along with an analysis of anticipated impacts.

Environmental patterns and biomass distribution of gelatinous macrozooplankton. Three study cases in the South-western Atlantic Ocean

Directory of Open Access Journals (Sweden)

H. W. Mianzan

2000-12-01

Full Text Available Periodic swarms or blooms of gelatinous macrozooplankton have a negative effect on many human activities such as tourism, fisheries, and industry, but for several reasons (sampling procedures, underestimation of their real abundance, etc., they have often been neglected in the local literature. The high spatial resolution exercise of the South-western Atlantic anchovy Engraulis anchoita Recruitment Project (SARP was therefore also suitable for estimating standing stocks of jelly macrozooplankton, attempting to establish particular environmental patterns exerting control on the spatial distribution of these facultative carnivorous predators in coastal frontal environments. These studies were carried out through a sampling programme on board the German R/V Meteor in three different systems, convergence and divergent, in the South-western Atlantic Ocean: Region A (42°S on the Argentine shelf, characterised by tidal mixing fronts; Region B (36°S, the freshwater outflow from Río de la Plata; and Region C (28°S, under upwelling events in subtropical waters on the Brazilian shelf. In general, a dominance of gelatinous macrozooplankton, compared with the other fraction of macrozooplankton and micronekton was observed. Mean standing stock of the gelatinous zooplankton was always greater than 50% of organic carbon (org. C in every section analysed. The lobate ctenophore Mnemiopsis leidyi dominated the zooplankton biomass in Region A, Argentina. It represented 60% of total org. C and was more abundant at the stratified zone of the front. Ctenophores were also dominant in Region B, Río de la Plata, where the related species Mnemiopsis mccradyi and the cydippid ctenophore Pleurobrachia pileus comprised 81% of total org. C. Mnemiopsis was most common in areas of vertical thermal and saline stratification, while Pleurobrachia was dominant in the less stratified areas. Gelatinous zooplankton was also the principal component of the macrozooplankton biomass

Role of tropical Indian and Atlantic Oceans variability on ENSO

Science.gov (United States)

Prodhomme, Chloé; Terray, Pascal; Masson, Sebastien; Boschat, Ghyslaine

2014-05-01

There are strong evidences of an interaction between tropical Indian, Atlantic and Pacific Oceans. Nevertheless, these interactions remain deeply controversial. While some authors claim the tropical Indian and Atlantic oceans only play a passive role with respect to ENSO, others suggest a driving role for these two basins on ENSO. The mecanisms underlying these relations are not fully understood and, in the Indian Ocean, the possible role of both modes of tropical variability (the Indian Ocean Dipole (IOD) and the Indian Ocean Basin mode (IOB)) remain unclear. To better quantify and understand how the variability of the tropical Indian and Atlantic Oceans impact ENSO variability, we performed two sensitivity experiments using the SINTEX-F2 coupled model. For each experiment, we suppressed the variability of SST and the air-sea coupling in either the tropical Indian Ocean or tropical Atlantic Ocean by applying a strong nudging of the SST to the observed SST climatology. In both experiments, the ENSO periodicity increases. In the Atlantic experiment, our understanding of this increased periodicity is drastically limited by the strongly biased mean state in this region. Conversely, in the Indian Ocean experiment, the increase of ENSO periodicity is related to the absence of the IOB following the El Niño peak, which leads to a decrease of westerly winds in the western Pacific during late winter and spring after the peak. These weaker westerlies hinders the transition to a La Niña phase and thus increase the duration and periodicity of the event.

Landscape Conservation and Social Tension in the Brazilian Atlantic Forest: Challenges for Implementing Sustainability

Science.gov (United States)

Libia Patricia Peralta Agudelo; Maristela Marangon

2006-01-01

The study is based in the Environmental Protection Area of Guaraqueçaba located in the Atlantic Forest of the State of Paraná, southern Brazil. EPAs in Brazil allow private ownership, resource extraction, and agriculture according to predefined land use laws. A systems’ approach was adopted to define the main interacting variables needed to understand the local socio-...

Local-scale models reveal ecological niche variability in amphibian and reptile communities from two contrasting biogeographic regions

Directory of Open Access Journals (Sweden)

Alberto Muñoz

2016-10-01

Full Text Available Ecological Niche Models (ENMs are widely used to describe how environmental factors influence species distribution. Modelling at a local scale, compared to a large scale within a high environmental gradient, can improve our understanding of ecological species niches. The main goal of this study is to assess and compare the contribution of environmental variables to amphibian and reptile ENMs in two Spanish national parks located in contrasting biogeographic regions, i.e., the Mediterranean and the Atlantic area. The ENMs were built with maximum entropy modelling using 11 environmental variables in each territory. The contributions of these variables to the models were analysed and classified using various statistical procedures (Mann–Whitney U tests, Principal Components Analysis and General Linear Models. Distance to the hydrological network was consistently the most relevant variable for both parks and taxonomic classes. Topographic variables (i.e., slope and altitude were the second most predictive variables, followed by climatic variables. Differences in variable contribution were observed between parks and taxonomic classes. Variables related to water availability had the larger contribution to the models in the Mediterranean park, while topography variables were decisive in the Atlantic park. Specific response curves to environmental variables were in accordance with the biogeographic affinity of species (Mediterranean and non-Mediterranean species and taxonomy (amphibians and reptiles. Interestingly, these results were observed for species located in both parks, particularly those situated at their range limits. Our findings show that ecological niche models built at local scale reveal differences in habitat preferences within a wide environmental gradient. Therefore, modelling at local scales rather than assuming large-scale models could be preferable for the establishment of conservation strategies for herptile species in natural

Local-scale models reveal ecological niche variability in amphibian and reptile communities from two contrasting biogeographic regions

Science.gov (United States)

Santos, Xavier; Felicísimo, Ángel M.

2016-01-01

Ecological Niche Models (ENMs) are widely used to describe how environmental factors influence species distribution. Modelling at a local scale, compared to a large scale within a high environmental gradient, can improve our understanding of ecological species niches. The main goal of this study is to assess and compare the contribution of environmental variables to amphibian and reptile ENMs in two Spanish national parks located in contrasting biogeographic regions, i.e., the Mediterranean and the Atlantic area. The ENMs were built with maximum entropy modelling using 11 environmental variables in each territory. The contributions of these variables to the models were analysed and classified using various statistical procedures (Mann–Whitney U tests, Principal Components Analysis and General Linear Models). Distance to the hydrological network was consistently the most relevant variable for both parks and taxonomic classes. Topographic variables (i.e., slope and altitude) were the second most predictive variables, followed by climatic variables. Differences in variable contribution were observed between parks and taxonomic classes. Variables related to water availability had the larger contribution to the models in the Mediterranean park, while topography variables were decisive in the Atlantic park. Specific response curves to environmental variables were in accordance with the biogeographic affinity of species (Mediterranean and non-Mediterranean species) and taxonomy (amphibians and reptiles). Interestingly, these results were observed for species located in both parks, particularly those situated at their range limits. Our findings show that ecological niche models built at local scale reveal differences in habitat preferences within a wide environmental gradient. Therefore, modelling at local scales rather than assuming large-scale models could be preferable for the establishment of conservation strategies for herptile species in natural parks. PMID

Rheological considerations for the modelling of submarine sliding at Rockall Bank, NE Atlantic Ocean

Science.gov (United States)

Salmanidou, D. M.; Georgiopoulou, A.; Guillas, S.; Dias, F.

2018-03-01

Recent scientific research indicates that the Rockall Bank Slide Complex in the NE Atlantic Ocean has formed as the result of repetitive slope failures that can be distinguished in at least three major phases. These sliding episodes took place during and before the Last Glacial Maximum. This work attempts the modelling of each sliding episode with the incorporation of the landslide's rheological properties. The objective is to study the landslide kinematics and final deposition of each episode under a rheological framework that comes in agreement with the field observations. To do so in the present work, we use different types of rheological models to compute the total retarding stress and simulate submarine failure. The Bingham rheology and the frictional rheology are used to model the flow behavior. The scope of this approach is to understand the effect of the two classical laws in landslide kinematics. A rheological model that combines the two regimes is also used. To account for the hydrodynamic drag, the Voellmy model is employed. The results are validated against the field observations on the seabed of the Rockall Trough. The simulations show that for this particular case the Bingham rheology with a small or negligible basal friction produces the best results. The tsunamigenic potential of the episodes is also briefly examined.

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...

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.

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

A review of mathematical models in economic environmental problems

DEFF Research Database (Denmark)

Nahorski, Z.; Ravn, H.F.

2000-01-01

The paper presents a review of mathematical models used,in economic analysis of environmental problems. This area of research combines macroeconomic models of growth, as dependent on capital, labour, resources, etc., with environmental models describing such phenomena like natural resources...... exhaustion or pollution accumulation and degradation. In simpler cases the models can be treated analytically and the utility function can be optimized using, e.g., such tools as the maximum principle. In more complicated cases calculation of the optimal environmental policies requires a computer solution....

The Red Atlantic: Transoceanic Cultural Exchanges

Science.gov (United States)

Weaver, Jace

2011-01-01

The development of David Armitage's "white Atlantic" history parallels the Cold War origins of American studies with its mission to define and promote "American culture" or "American civilization." British scholar Paul Gilroy's "The Black Atlantic" served as a necessary corrective. Armitage's statement leads…

Conference-EC-US Task Force Joint US-EU Workshop on Metabolomics and Environmental Biotechnology

Energy Technology Data Exchange (ETDEWEB)

PI: Lily Y. Young

2009-06-04

Since 1990, the EC-US Task Force on Biotechnology Research has been coordinating transatlantic efforts to guide and exploit the ongoing revolution in biotechnology and the life sciences. The Task Force was established in June 1990 by the European Commission and the White House Office of Science and Technology Policy. The Task Force has acted as an effective forum for discussion, coordination, and development of new ideas for the last 18 years. Task Force members are European Commission and US Government science and technology administrators who meet annually to enhance communication across the Atlantic, and to encourage collaborative research. Through sponsoring workshops, and other activities, the Task Force also brings together scientific leaders and early career researchers from both sides of the Atlantic to forecast research challenges and opportunities and to promote better links between researchers. Over the years, by keeping a focus on the future of science, the Task Force has played a key role in establishing a diverse range of emerging scientific fields, including biodiversity research, neuroinformatics, genomics, nanobiotechnology, neonatal immunology, transkingdom molecular biology, biologically-based fuels, and environmental biotechnology. The EC-US Task Force has sponsored a number of Working Groups on topics of mutual transatlantic interest. The idea to create a Working Group on Environmental Biotechnology research was discussed in the Task Force meeting of October 1993. The EC-US Working Group on Environmental Biotechnology set as its mission 'To train the next generation of leaders in environmental biotechnology in the United States and the European Union to work collaboratively across the Atlantic.' Since 1995, the Working Group supported three kinds of activities, all of which focus one early career scientists: (1) Workshops on the use of molecular methods and genomics in environmental biotechnology; (2) Short courses with theoretical

Restoration practicesin Brazil's Atlantic rainforest.

Science.gov (United States)

Jorge Correa de Lima Palidon; Maisa dos Santos Guapyassu

2005-01-01

The atlantic Rain Forst (Mata Atlantica) extends along the southern coast of Brazil and inland into Argentina and Paraguay. Originally covering 15% of the land area of Brazil, it was a region of an estimated 1.3 million km2 (MMA 2000). Today, remnants of the Atlantic Forest represents about 8% of the original area, or some 94,000 km2...

An Atlantic streamer in stratospheric ozone observations and SD-WACCM simulation data

Science.gov (United States)

Hocke, Klemens; Schranz, Franziska; Maillard Barras, Eliane; Moreira, Lorena; Kämpfer, Niklaus

2017-03-01

Observation and simulation of individual ozone streamers are important for the description and understanding of non-linear transport processes in the middle atmosphere. A sudden increase in mid-stratospheric ozone occurred above central Europe on 4 December 2015. The GROund-based Millimeter-wave Ozone Spectrometer (GROMOS) and the Stratospheric Ozone MOnitoring RAdiometer (SOMORA) in Switzerland measured an ozone enhancement of about 30 % at 34 km altitude (8.3 hPa) from 1 to 4 December. A similar ozone increase is simulated by the Specified Dynamics Whole Atmosphere Community Climate (SD-WACCM) model. Further, the global ozone fields at 34 km altitude (8.3 hPa) from SD-WACCM and the satellite experiment Aura/MLS show a remarkable agreement for the location and timing of an ozone streamer (large-scale tongue-like structure) extending from the subtropics in northern America over the Atlantic to central Europe. This agreement indicates that SD-WACCM can inform us about the wind inside the Atlantic ozone streamer. SD-WACCM shows an eastward wind of about 100 m s-1 inside the Atlantic streamer in the mid-stratosphere. SD-WACCM shows that the Atlantic streamer flows along the edge of the polar vortex. The Atlantic streamer turns southward at an erosion region of the polar vortex located above the Caspian Sea. The spatial distribution of stratospheric water vapour indicates a filament outgoing from this erosion region. The Atlantic streamer, the polar vortex erosion region and the water vapour filament belong to the process of planetary wave breaking in the so-called surf zone of the northern midlatitude winter stratosphere.

The energy sector : an investment in the people and communities of Atlantic Canada

International Nuclear Information System (INIS)

2008-01-01

The opportunity for Atlantic Canada to meet the North American demand for more energy and increased security was discussed. Energy accounts for nearly half of all exports from Atlantic Canada. The region delivers oil, natural gas and electricity to its own communities and for export around the continent and is poised to significantly increase its reach, given its proximity to the New England States. Over the past decade, the energy industry in Atlantic Canada has laid the foundation for what has become one of the most significant sectors in the regional economy. It has a diverse mix of traditional thermal and hydroelectric generation with newer technology such as nuclear, wind, bioenergy and tidal. The discovery and development of offshore oil and gs fields at the end of the twentieth century significantly enhanced the regional energy sector and shifted the public policy focus from domestic production to the development of export markets. The projects have brought significant outside investment from a broad range of oil and gas companies. This paper listed the projects and players in the energy sector in New Brunswick, Nova Scotia, Prince Edward Island, and Newfoundland and Labrador. The issue of exporting energy resources and importing human resources was also considered. A list of skilled trades, professional services and support services that will be needed by the Atlantic Canadian energy sector over the next decade was also provided. It was noted that employment growth is driven by demographics, technology and the trend for environmental stewardship. 9 refs., 2 tabs

Coupled ocean-atmosphere surface variability and its climate impacts in the tropical Atlantic region

Science.gov (United States)

Fontaine, B.; Janicot, Serge; Roucou, P.

This study examines time evolution and statistical relationships involving the two leading ocean-atmosphere coupled modes of variability in the tropical Atlantic and some climate anomalies over the tropical 120°W-60°W region using selected historical files (75-y near global SSTs and precipitation over land), more recent observed data (30-y SST and pseudo wind stress in the tropical Atlantic) and reanalyses from the US National Centers for Environmental Prediction (NCEP/NCAR) reanalysis System on the period 1968-1997: surface air temperature, sea level pressure, moist static energy content at 850 hPa, precipitable water and precipitation. The first coupled mode detected through singular value decomposition of the SST and pseudo wind-stress data over the tropical Atlantic (30°N-20°S) expresses a modulation in the thermal transequatorial gradient of SST anomalies conducted by one month leading wind-stress anomalies mainly in the tropical north Atlantic during northern winter and fall. It features a slight dipole structure in the meridional plane. Its time variability is dominated by a quasi-decadal signal well observed in the last 20-30 ys and, when projected over longer-term SST data, in the 1920s and 1930s but with shorter periods. The second coupled mode is more confined to the south-equatorial tropical Atlantic in the northern summer and explains considerably less wind-stress/SST cross-covariance. Its time series features an interannual variability dominated by shorter frequencies with increased variance in the 1960s and 1970s before 1977. Correlations between these modes and the ENSO-like Nino3 index lead to decreasing amplitude of thermal anomalies in the tropical Atlantic during warm episodes in the Pacific. This could explain the nonstationarity of meridional anomaly gradients on seasonal and interannual time scales. Overall the relationships between the oceanic component of the coupled modes and the climate anomaly patterns denote thermodynamical

Food selection among Atlantic Coast seaducks in relation to historic food habits

Science.gov (United States)

Perry, M.C.; Osenton, P.C.; Wells-Berlin, A. M.; Kidwell, D.M.

2005-01-01

Food selection among Atlantic Coast seaducks during 1999-2005 was determined from hunter-killed ducks and compared to data from historic food habits file (1885-1985) for major migrational and wintering areas in the Atlantic Flyway. Food selection was determined by analyses of the gullet (esophagus and proventriculus) and gizzard of 860 ducks and summarized by aggregate percent for each species. When sample size was adequate comparisons were made among age and sex groupings and also among local sites in major habitat areas. Common eiders in Maine and the Canadian Maritimes fed predominantly (53%) on the blue mussel (Mytilus edulis). Scoters in Massachusetts, Maine, and the Canadian Maritimes fed predominantly on the blue mussel (46%), Atlantic jackknife clam (Ensis directus; 19%), and Atlantic surf clam (Spisula solidissima; 15%), whereas scoters in the Chesapeake Bay fed predominantly on hooked mussel (Ischadium recurvum; 42%), the stout razor clam (Tagelus plebeius; 22%), and dwarf surf clam (Mulinia lateralis; 15%). The amethyst gem clam (Gemma gemma) was the predominant food (45%) of long-tailed ducks in Chesapeake Bay. Buffleheads and common goldeneyes fed on a mixed diet of mollusks and soft bodied invertebrates (amphipods, isopods and polychaetes). No major differences were noticed between the sexes in regard to food selection in any of the wintering areas. Comparisons to historic food habits in all areas failed to detect major differences. However, several invertebrate species recorded in historic samples were not found in current samples and two invasive species (Atlantic Rangia, Rangia cuneata and green crab, Carcinas maenas) were recorded in modem samples, but not in historic samples. Benthic sampling in areas where seaducks were collected showed a close correlation between consumption and availability. Each seaduck species appears to fill a unique niche in regard to feeding ecology, although there is much overlap of prey species selected. Understanding

Proceedings of the 2009 Atlantic reclamation conference

Energy Technology Data Exchange (ETDEWEB)

NONE

2009-07-01

This conference provided a forum for industry leaders of reclamation and restoration to advance knowledge, raise awareness and examine problems and solutions in the areas of land and waterway reclamation, restoration and rehabilitation. With a history of resource and industrial development, many communities in Atlantic Canada are faced with the challenge of restoring contaminated sites and abandoned mines sites, including both underground and surface coal mines. The topics discussed at this conference ranged from mine site reclamation, in-situ and ex-situ remediation, contaminated site restoration, erosion and sediment control planning, revegetation planning, wetland and soil quality research, landuse planning, regulation, and environmental risk. One of the 25 presentations featured at this conference has been catalogued separately for inclusion in this database. tabs., figs.

Comparison of Drosophilidae (Diptera) assemblages from two highland Araucaria Forest fragments, with and without environmental conservation policies

OpenAIRE

Cavasini, R; Buschini, MLT; Machado, LPB; Mateus, RP

2014-01-01

Flies from the Drosophilidae family are model organisms for biological studies and are often suggested as bioindicators of environmental quality. The Araucaria Forest, one of Atlantic Forest phyto-physiognomy, displays a highly fragmented distribution due to the expansion of agriculture and urbanization. Thus, this work aimed to evaluate and compare the drosophilid assemblages from two highland Araucaria Forest fragments, one a conservation unit (PMA – Parque Municipal das Araucárias) and the...

A resource oriented webs service for environmental modeling

Science.gov (United States)

Ferencik, Ioan

2013-04-01

Environmental modeling is a largely adopted practice in the study of natural phenomena. Environmental models can be difficult to build and use and thus sharing them within the community is an important aspect. The most common approach to share a model is to expose it as a web service. In practice the interaction with this web service is cumbersome due to lack of standardized contract and the complexity of the model being exposed. In this work we investigate the use of a resource oriented approach in exposing environmental models as web services. We view a model as a layered resource build atop the object concept from Object Oriented Programming, augmented with persistence capabilities provided by an embedded object database to keep track of its state and implementing the four basic principles of resource oriented architectures: addressability, statelessness, representation and uniform interface. For implementation we use exclusively open source software: Django framework, dyBase object oriented database and Python programming language. We developed a generic framework of resources structured into a hierarchy of types and consequently extended this typology with recurses specific to the domain of environmental modeling. To test our web service we used cURL, a robust command-line based web client.

Spatial transferability of habitat suitability models of Nephrops norvegicus among fished areas in the Northeast Atlantic: sufficiently stable for marine resource conservation?

Directory of Open Access Journals (Sweden)

Valentina Lauria

Full Text Available Knowledge of the spatial distribution and habitat associations of species in relation to the environment is essential for their management and conservation. Habitat suitability models are useful in quantifying species-environment relationships and predicting species distribution patterns. Little is known, however, about the stability and performance of habitat suitability models when projected into new areas (spatial transferability and how this can inform resource management. The aims of this study were to model habitat suitability of Norway lobster (Nephrops norvegicus in five fished areas of the Northeast Atlantic (Aran ground, Irish Sea, Celtic Sea, Scotland Inshore and Fladen ground, and to test for spatial transferability of habitat models among multiple regions. Nephrops burrow density was modelled using generalised additive models (GAMs with predictors selected from four environmental variables (depth, slope, sediment and rugosity. Models were evaluated and tested for spatial transferability among areas. The optimum models (lowest AICc for different areas always included depth and sediment as predictors. Burrow densities were generally greater at depth and in finer sediments, but relationships for individual areas were sometimes more complex. Aside from an inclusion of depth and sediment, the optimum models differed between fished areas. When it came to tests of spatial transferability, however, most of the models were able to predict Nephrops density in other areas. Furthermore, transferability was not dependent on use of the optimum models since competing models were also able to achieve a similar level of transferability to new areas. A degree of decoupling between model 'fitting' performance and spatial transferability supports the use of simpler models when extrapolating habitat suitability maps to different areas. Differences in the form and performance of models from different areas may supply further information on the processes

Mechanisms for decadal scale variability in a simulated Atlantic meridional overturning circulation

Energy Technology Data Exchange (ETDEWEB)

Medhaug, I.; Eldevik, T.; Furevik, T. [University of Bergen, Geophysical Institute, Bergen (Norway); Bjerknes Centre for Climate Research, Bergen (Norway); Langehaug, H.R. [Nansen Environmental and Remote Sensing Center, Bergen (Norway); Bjerknes Centre for Climate Research, Bergen (Norway); Bentsen, M. [Uni Bjerknes Centre, Uni Research, Bergen (Norway); Bjerknes Centre for Climate Research, Bergen (Norway)

2012-07-15

Variability in the Atlantic Meridional Overturning Circulation (AMOC) has been analysed using a 600-year pre-industrial control simulation with the Bergen Climate Model. The typical AMOC variability has amplitudes of 1 Sverdrup (1 Sv = 10{sup 6} m{sup 3} s{sup -1}) and time scales of 40-70 years. The model is reproducing the observed dense water formation regions and has very realistic ocean transports and water mass distributions. The dense water produced in the Labrador Sea (1/3) and in the Nordic Seas, including the water entrained into the dense overflows across the Greenland-Scotland Ridge (GSR; 2/3), are the sources of North Atlantic Deep Water (NADW) forming the lower limb of the AMOC's northern overturning. The variability in the Labrador Sea and the Nordic Seas convection is driven by decadal scale air-sea fluxes in the convective region that can be related to opposite phases of the North Atlantic Oscillation. The Labrador Sea convection is directly linked to the variability in AMOC. Linkages between convection and water mass transformation in the Nordic Seas are more indirect. The Scandinavian Pattern, the third mode of atmospheric variability in the North Atlantic, is a driver of the ocean's poleward heat transport (PHT), the overall constraint on northern water mass transformation. Increased PHT is both associated with an increased water mass exchange across the GSR, and a stronger AMOC. (orig.)

South Atlantic meridional transports from NEMO-based simulations and reanalyses

Science.gov (United States)

Mignac, Davi; Ferreira, David; Haines, Keith

2018-02-01

The meridional heat transport (MHT) of the South Atlantic plays a key role in the global heat budget: it is the only equatorward basin-scale ocean heat transport and it sets the northward direction of the global cross-equatorial transport. Its strength and variability, however, are not well known. The South Atlantic transports are evaluated for four state-of-the-art global ocean reanalyses (ORAs) and two free-running models (FRMs) in the period 1997-2010. All products employ the Nucleus for European Modelling of the Oceans (NEMO) model, and the ORAs share very similar configurations. Very few previous works have looked at ocean circulation patterns in reanalysis products, but here we show that the ORA basin interior transports are consistently improved by the assimilated in situ and satellite observations relative to the FRMs, especially in the Argo period. The ORAs also exhibit systematically higher meridional transports than the FRMs, which is in closer agreement with observational estimates at 35 and 11° S. However, the data assimilation impact on the meridional transports still greatly varies among the ORAs, leading to differences up to ˜ 8 Sv and 0.4 PW in the South Atlantic Meridional Overturning Circulation and the MHTs, respectively. We narrow this down to large inter-product discrepancies in the western boundary currents (WBCs) at both upper and deep levels explaining up to ˜ 85 % of the inter-product differences in MHT. We show that meridional velocity differences, rather than temperature differences, in the WBCs drive ˜ 83 % of this MHT spread. These findings show that the present ocean observation network and data assimilation schemes can be used to consistently constrain the South Atlantic interior circulation but not the overturning component, which is dominated by the narrow western boundary currents. This will likely limit the effectiveness of ORA products for climate or decadal prediction studies.

Uncertainty quantification for environmental models

Science.gov (United States)

Hill, Mary C.; Lu, Dan; Kavetski, Dmitri; Clark, Martyn P.; Ye, Ming

2012-01-01

Environmental models are used to evaluate the fate of fertilizers in agricultural settings (including soil denitrification), the degradation of hydrocarbons at spill sites, and water supply for people and ecosystems in small to large basins and cities—to mention but a few applications of these models. They also play a role in understanding and diagnosing potential environmental impacts of global climate change. The models are typically mildly to extremely nonlinear. The persistent demand for enhanced dynamics and resolution to improve model realism [17] means that lengthy individual model execution times will remain common, notwithstanding continued enhancements in computer power. In addition, high-dimensional parameter spaces are often defined, which increases the number of model runs required to quantify uncertainty [2]. Some environmental modeling projects have access to extensive funding and computational resources; many do not. The many recent studies of uncertainty quantification in environmental model predictions have focused on uncertainties related to data error and sparsity of data, expert judgment expressed mathematically through prior information, poorly known parameter values, and model structure (see, for example, [1,7,9,10,13,18]). Approaches for quantifying uncertainty include frequentist (potentially with prior information [7,9]), Bayesian [13,18,19], and likelihood-based. A few of the numerous methods, including some sensitivity and inverse methods with consequences for understanding and quantifying uncertainty, are as follows: Bayesian hierarchical modeling and Bayesian model averaging; single-objective optimization with error-based weighting [7] and multi-objective optimization [3]; methods based on local derivatives [2,7,10]; screening methods like OAT (one at a time) and the method of Morris [14]; FAST (Fourier amplitude sensitivity testing) [14]; the Sobol' method [14]; randomized maximum likelihood [10]; Markov chain Monte Carlo (MCMC) [10

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.

Turbidity distribution in the Atlantic Ocean

Science.gov (United States)

Eittreim, S.; Thorndike, E.M.; Sullivan, L.

1976-01-01

The regional coverage of Lamont nephelometer data in the North and South Atlantic can be used to map seawater turbidity at all depths. At the level of the clearest water, in the mid-depth regions, the turbidity distribution primarily reflects the pattern of productivity in the surface waters. This suggests that the 'background' turbidity level in the oceans is largely a function of biogenic fallout. The bottom waters of the western Atlantic generally exhibit large increases in turbidity. The most intense benthic nepheloid layers are in the southwestern Argentine basin and northern North American basin; the lowest bottom water turbidity in the western Atlantic is in the equatorial regions. Both the Argentine and North American basin bottom waters appear to derive their high turbidity largely from local resuspension of terrigenous input in these basins. In contrast to the west, the eastern Atlantic basins show very low turbidities with the exception of three regions: the Mediterranean outflow area, the Cape basin, and the West European basin. ?? 1976.

Environmental contaminants in fillets of sea-run Atlantic salmon (Salmo salar) from the Gulf of Maine Distinct Population Segment

Data.gov (United States)

Department of the Interior — Between 2008 and 2010, skin‐on fillets from seven dead adult sea‐run Atlantic salmon from the Gulf of Maine Distinct Population Segment (GOM DPS) were analyzed for...

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.)

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.

Regional model simulation of the North Atlantic cyclone "Caroline" and comparisons with satellite data

Directory of Open Access Journals (Sweden)

E. Keup-Thiel

2003-03-01

Full Text Available An individual regional model simulation of cyclone "Caroline" has been carried out to study water cycle components over the North Atlantic Ocean. The uncertainties associated with quantitative estimates of the water cycle components are highlighted by a comparison of the model results with SSM/I (Special Sensor Microwave Imager satellite data. The vertically integrated water vapor of the REgional MOdel REMO is in good agreement with the SSM/I satellite data. The simulation results for other water budget components like the vertically integrated liquid water content and precipitation compare also reasonably well within the frontal system. However, the high precipitation rate in the cold air outbreak on the backside of the cold front derived from SSM/I satellite data is generally underestimated by REMO. This results in a considerable deficit of the total precipitation amount accumulated for the cyclone "Caroline". While REMO simulates 24.3 108 m3 h-1 for 09:00 UTC, the total areal precipitation from SSM/I satellite data amounts to 54.7 08 m3 h-1.Key words. Meteorology and atmospheric dynamics (precipitation; mesoscale meteorology – Radio science (remote sensing

Conceptual ecological model for management of breeding shrubland birds in the Mid-Atlantic Region

Science.gov (United States)

Peterjohn, Bruce G.

2006-01-01

communities. This project involved parks within three NPS Inventory and Monitoring Program (I&M) networks, Mid-Atlantic, National Capital, and Eastern Rivers and Mountains. Five parks were selected for the initial focus of this study, all of which maintain open landscapes for interpreting historic events. Most parks were selected because they contain the most extensive grassland habitats within their networks, although some also support shrubby successional habitats. The five parks included in this study are Antietam National Battlefield, Fort Necessity National Battlefield, Gettysburg National Battlefield, Manassas National Battlefield, and Monocacy National Battlefield. This conceptual ecological model is one product of this project. The information presented below allows NPS network coordinators to understand which factors should be considered when making decisions concerning shrubland management within their networks. This model provides park resource managers with information on shrubland ecology in the Mid-Atlantic Region, the ecological requirements of shrubland birds likely to occur in their parks, and management issues influencing whether significant breeding populations can occupy shrublands created and maintained in the parks. Resource managers can then make informed decisions concerning their ability to create and maintain shrubland habitats. The emphasis of this conceptual model is restricted to management of breeding shrubland birds. Additional species occur during migration and winter, and habitat requirements of shrubland birds during nonbreeding seasons may differ from those described for the breeding season.

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

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 ...

Environmental Parametric Cost Model in Oil and Gas EPC Contracts

Directory of Open Access Journals (Sweden)

Madjid Abbaspour

2018-01-01

Full Text Available This study aims at identifying the parameters that govern the environmental costs in oil and gas projects. An initial conceptual model was proposed. Next, the costs of environmental management work packages were estimated, separately and were applied in project control tools (WBS/CBS. Then, an environmental parametric cost model was designed to determine the environmental costs and relevant weighting factors. The suggested model can be considered as an innovative approach to designate the environmental indicators in oil and gas projects. The validity of variables was investigated based on Delphi method. The results indicated that the project environmental management’s weighting factor is 0.87% of total project’s weighting factor.

Comparative biology and population mixing among local, coastal and offshore Atlantic herring (Clupea harengus) in the North Sea, Skagerrak, Kattegat and western Baltic

Science.gov (United States)

Slotte, Aril; Johannessen, Arne; Kvamme, Cecilie; Clausen, Lotte Worsøe; Nash, Richard D. M.

2017-01-01

The population structure of Atlantic herring (Clupea harengus) from 13 local, coastal and offshore areas of the North Sea, Skagerrak, Kattegat and western Baltic (northeast Atlantic) was studied using biological and environmental data from 1970–2015. The objective was to identify distinct populations by comparing variability in the temporal and spatial phenotypic characteristics and evaluate the potential for mixing of populations in time and space. The populations varied in biological characteristics such as mean vertebral counts (VS), growth and maturity ogives. Generalized additive models indicated temporally stable VS in the North Sea and western Baltic, whereas intra-annual temporal variation of VS occurred in other areas. High variability of VS within a population was not affected by environmental factors such as temperature and salinity. Consequently, seasonal VS variability can be explained by the presence or absence of herring populations as they migrate between areas. The three main populations identified in this paper correspond to the three managed stocks in this area: Norwegian spring spawners (NSS), western Baltic spring spawners (WBSS) and North Sea autumn spawners (NSAS). In addition, several local populations were identified in fjords or lakes along the coast, but our analyses could not detect direct mixing of local populations with the three main populations. Our results highlight the importance of recognizing herring dynamics and understanding the mixing of populations as a challenge for management of herring. PMID:29084258

Atlantic menhaden processing plant test tagging data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Atlantic menhaden are a schooling forage fish species, which are subject to a large commercial purse seine fishery. Atlantic menhaden are harvested for reduction...

The effect of nonylphenol on gene expression in Atlantic salmon smolts

Energy Technology Data Exchange (ETDEWEB)

Robertson, Laura S., E-mail: lrobertson@usgs.gov [USGS, Leetown Science Center, 11649 Leetown Road, Kearneysville, WV 25430 (United States); McCormick, Stephen D., E-mail: smccormick@usgs.gov [USGS, Leetown Science Center, Conte Anadromous Fish Research Center, Turners Falls, MA 01376 (United States)

2012-10-15

The parr-smolt transformation in Atlantic salmon (Salmo salar) is a complex developmental process that culminates in the ability to migrate to and live in seawater. Exposure to environmental contaminants like nonylphenol can disrupt smolt development and may be a contributing factor in salmon population declines. We used GRASP 16K cDNA microarrays to investigate the effects of nonylphenol on gene expression in Atlantic salmon smolts. Nonylphenol exposure reduced gill Na{sup +}/K{sup +}-ATPase activity and plasma cortisol and triiodothyronine levels. Transcriptional responses were examined in gill, liver, olfactory rosettes, hypothalamus, and pituitary. Expression of 124 features was significantly altered in the liver of fish exposed to nonylphenol; little to no transcriptional effects were observed in other tissues. mRNA abundance of genes involved in protein biosynthesis, folding, modification, transport and catabolism; nucleosome assembly, cell cycle, cell differentiation, microtubule-based movement, electron transport, and response to stress increased in nonylphenol-treated fish. This study expands our understanding of the effect of nonylphenol on smolting and provides potential targets for development of biomarkers.

The Atlantic Seaduck Project: Medical Aspects

Science.gov (United States)

Olsen, Glenn H.; Perry, M.C.; Wells, A.M.; Lohnes, E.J.R.; Osenton, P.C.

2005-01-01

Some populations of seaducks, especially scoters along the Atlantic Coast, have been declining over recent decades. A joint US-Canadian tearn has been working to capture and surgically implant satellite radio transmitters in these ducks. Black scoters (Melanitta nigra) captured on the Restigouche River in New Brunswick, Canada and surf scoters (M. perspicilata) captured on Chesapeake Bay, Maryland, USA have been tracked by the use of Argos/NOAA polar orbiting operational environmental satellites to their breeding and molting areas and back south to their wintering ranges. Successful capture techniques included night-lighting and a capture net gun. A captive colony of seaducks has been maintained for feeding habits and nutritional studies. Veterinary medicine has played a key role in the surgical implantation of the satellite transmitters and in developing heath procedures for the captive seaduck colony.

Abundance of small mammals in the Atlantic Forest (ASMAF): a data set for analyzing tropical community patterns.

Science.gov (United States)

Figueiredo, Marcos S L; Barros, Camila S; Delciellos, Ana C; Guerra, Edú B; Cordeiro-Estrela, Pedro; Kajin, Maja; Alvarez, Martin R; Asfora, Paulo H; Astúa, Diego; Bergallo, Helena G; Cerqueira, Rui; Geise, Lena; Gentile, Rosana; Grelle, Carlos Eduardo V; Iack-Ximenes, Gilson E; Oliveira, Leonardo C; Weksler, Marcelo; Vieira, Marcus V

2017-11-01

Local abundance results from the interaction between populational and environmental processes. The abundance of the species in a community is also one of the most basic descriptors of its structure. Despite its importance, information about species abundances is fragmentary, creating a knowledge gap about species abundances known as the Prestonian Shortfall. Here we present a comprehensive data set of small mammal abundance in the Atlantic Forest. Data were extracted from 114 published sources and from unpublished data collected by our research groups spanning from 1943 to 2017. The data set includes 1,902 records of at least 111 species in 155 localities, totaling 42,617 individuals represented. We selected studies that (1) were conducted in forested habitats of the Atlantic Forest, (2) had a minimum sampling effort of at least 500 trap-nights, and (3) contained species abundance data in detail. For each study, we recorded (1) latitude and longitude, (2) name of the locality, (3) employed sampling effort, (4) type of traps used, (5) study year, (6) country, and (7) species name with (8) its respective abundances. For every locality, we also obtained information regarding its (9) ecoregion, (10) predominant vegetation type, and (11) biogeographic subdivision. Whenever necessary, we also (12) updated the species names as new species were described and some genera suffered taxonomic revision since the publication. The localities are spread across the Atlantic Forest and most of the small mammal species known to occur in Atlantic Forest are present in the data set, making it representative of communities of the entire biome. This data set can be used to address various patterns in community ecology and geographical ecology, as the relation between local abundance and environmental suitability, hypothesis regarding local and regional factors on community structuring, species abundance distributions (SAD), functional and phylogenetic mechanisms on community assembling

A goal programming model for environmental policy analysis: Application to Spain

International Nuclear Information System (INIS)

San Cristóbal, José Ramón

2012-01-01

Sustainable development has become an important part of international and national approaches to integrate economic, environmental, social and ethical considerations so that a good quality of life can be enjoyed by current and future generations for as long as possible. However, nowadays sustainable development is threatened by industrial pollution emissions which cause serious environmental problems. Due to a lack of adequate quantitative models for environmental policy analysis, there is a strong need for analytical models in order to know the effects of environmental policies. In the present paper, a goal programming model, based on an environmental/input–output linear programming model, is developed and applied to the Spanish economy. The model combines relations between economic, energy, social and environmental effects, providing valuable information for policy-makers in order to define and examine the different goals that must be implemented to reach sustainability. - Highlights: ► In this paper a goal programming model is developed. ► The model considers environmental, energy, social and economic goals. ► The model shows the effects of a reduction in greenhouse gasses emission and energy requirements. ► The model is applied to the Spanish economy.

18th Middle Atlantic Regional Meeting, American Chemical Society

International Nuclear Information System (INIS)

Anon.

1985-01-01

The Proceedings of the 18th Middle Atlantic Regional Meeting of the American Chemical Society held May 21-23, 1984, include information about the meeting, e.g. area map and list of exhibitors, and abstracts for most of the 397 papers. A few papers are only title listed. The papers are arranged into sections dealing with analytical chemistry, biochemistry, chemical education, environmental chemistry, fuel chemistry, history of chemistry, industrial and engineering chemistry, inorganic chemistry, photochemistry, physical chemistry, polymer chemistry, and polymeric materials. Sections are also included to highlight undergraduate research and papers by chemical technicians and younger chemists. Separate abstracts have been prepared for 36 papers

Parallel evolution and adaptation to environmental factors in a marine flatfish

DEFF Research Database (Denmark)

do Prado, Fernanda Dotti; Vera, Manuel; Hermida, Miguel

2018-01-01

frequency data from 755 single nucleotide polymorphism discovered and genotyped by double-digest RAD sequencing. The species was structured into four main regions: Baltic Sea, Atlantic Ocean, Adriatic Sea, and Black Sea, with subtle differentiation apparent at the distribution margins of the Atlantic region...... were probably the main environmental drivers of selection. Mining around the four genomic regions consistently inferred to be under selection identified candidate genes related to osmoregulation, growth, and resistance to diseases. The new insights are useful for the management of turbot fisheries...

An Integrated Environmental Assessment of the US Mid-Atlantic Region

Science.gov (United States)

James D. Wickham; K.B. Jones; Kurt H. Riitters; R.V. O' Neill; R.D. Tankersley; E.R. Smith; A.C. Neale; D.J. Chaloud

1999-01-01

Many of today's environmental problems are in scope and their effects overlap and interact. We developed a simple method to provide an integrated assessment of environmental conditions and estimate cumulative impacts across a large region, by combining data on land-cover, population, roads, streams, air pollution, and topography. The integrated assessment...

Harvesting Atlantic Cod under Climate Variability

Science.gov (United States)

Oremus, K. L.

2016-12-01

Previous literature links the growth of a fishery to climate variability. This study uses an age-structured bioeconomic model to compare optimal harvest in the Gulf of Maine Atlantic cod fishery under a variable climate versus a static climate. The optimal harvest path depends on the relationship between fishery growth and the interest rate, with higher interest rates dictating greater harvests now at the cost of long-term stock sustainability. Given the time horizon of a single generation of fishermen under assumptions of a static climate, the model finds that the economically optimal management strategy is to harvest the entire stock in the short term and allow the fishery to collapse. However, if the biological growth of the fishery is assumed to vary with climate conditions, such as the North Atlantic Oscillation, there will always be pulses of high growth in the stock. During some of these high-growth years, the growth of the stock and its economic yield can exceed the growth rate of the economy even under high interest rates. This implies that it is not economically optimal to exhaust the New England cod fishery if NAO is included in the biological growth function. This finding may have theoretical implications for the management of other renewable yet exhaustible resources whose growth rates are subject to climate variability.

Environmental Management Model for Road Maintenance Operation Involving Community Participation

Science.gov (United States)

Triyono, A. R. H.; Setyawan, A.; Sobriyah; Setiono, P.

2017-07-01

Public expectations of Central Java, which is very high on demand fulfillment, especially road infrastructure as outlined in the number of complaints and community expectations tweeter, Short Mail Massage (SMS), e-mail and public reports from various media, Highways Department of Central Java province requires development model of environmental management in the implementation of a routine way by involving the community in order to fulfill the conditions of a representative, may serve road users safely and comfortably. This study used survey method with SEM analysis and SWOT with Latent Independent Variable (X), namely; Public Participation in the regulation, development, construction and supervision of road (PSM); Public behavior in the utilization of the road (PMJ) Provincial Road Service (PJP); Safety in the Provincial Road (KJP); Integrated Management System (SMT) and latent dependent variable (Y) routine maintenance of the provincial road that is integrated with the environmental management system and involve the participation of the community (MML). The result showed the implementation of routine maintenance of road conditions in Central Java province has yet to implement an environmental management by involving the community; Therefore developed environmental management model with the results of H1: Community Participation (PSM) has positive influence on the Model of Environmental Management (MML); H2: Behavior Society in Jalan Utilization (PMJ) positive effect on Model Environmental Management (MML); H3: Provincial Road Service (PJP) positive effect on Model Environmental Management (MML); H4: Safety in the Provincial Road (KJP) positive effect on Model Environmental Management (MML); H5: Integrated Management System (SMT) has positive influence on the Model of Environmental Management (MML). From the analysis obtained formulation model describing the relationship / influence of the independent variables PSM, PMJ, PJP, KJP, and SMT on the dependent variable

Urban elementary students' views of environmental scientists, environmental caretakers and environmentally responsible behaviors

Science.gov (United States)

Horne, Patricia Lynne

The purpose of this research was to determine the nature of the relationship between urban elementary fifth graders, environmental workers, and the environment. The study examined 320 urban fifth grade elementary students' drawings of environmental scientists (DAEST) and environmental caretakers (DAECT). Additionally, semi-structured interviews were included to elucidate student illustrations. The study's sample represented one-third of all fifth graders in the mid-Atlantic school district selected for this research. Approximately 5% of participants were chosen for follow-up semi-structured interviews based on their illustrations. A general conclusion is some of the stereotypes, particularly related to gender, revealed in prior research (Barman, 1999, Chambers, 1983; Huber & Burton, 1995; Schibeci & Sorensen's, 1983; Sumrall, 1995) are evident among many elementary students. Male environmental scientists were drawn twice as often as female environmental scientists. Females were represented in more pictures of environmental caretakers than environmental scientists. Students overwhelmingly drew environmental scientists (98.1%) and environmental caretakers (76.5%) working alone. Wildlife was noticeably absent from most drawings (85%). Where wildlife was included, it was most often birds (6.9%) and fish (3.1%). More than one species was evident in only 2.5% of the pictures. Fifty percent of environmental caretakers were shown picking up trash from land. Actions such as reducing resource use occurred in only 13 out of 319 pictures (4.1%). Pictures of environmental caretakers sharing knowledge were even less common (2.5%). Almost 22% of females drew multiple individuals compared to 18.5% drawn by males. Females were more likely to show individuals collaborating (22.4% to 16.8%) while males were more likely to show individuals working in opposition (5.2% to 2.0%).

Modeling dust emission response to North Atlantic millennial-scale climate variations from the perspective of East European MIS 3 loess deposits

Directory of Open Access Journals (Sweden)

A. Sima

2013-07-01

Full Text Available European loess sequences of the Marine Isotope Stage 3 (~60–25 kyr BP show periods of strong dust accumulation alternating with episodes of reduced sedimentation, favoring soil development. In the western part of the loess belt centered around 50° N, these variations appear to have been related to the North Atlantic rapid climate changes: the Dansgaard–Oeschger (DO and Heinrich (H events. It has been recently suggested that the North Atlantic climate signal can be detected further east, in loess deposits from Stayky (50°05.65' N, 30°53.92' E, Ukraine. Here we use climate and dust emission modeling to investigate this data interpretation. We focus on the areas north and northeast of the Carpathians, where loess deposits can be found, and the corresponding main dust sources must have been located as well. The simulations were performed with the LMDZ atmospheric general circulation model and the ORCHIDEE land surface model. They represent a reference "Greenland stadial" state and two perturbations, seen as sensitivity tests with respect to changes in the North Atlantic surface conditions between 30° and 63° N: a "Greenland interstadial" and an "H event". The main source for the loess deposits in the studied area is identified as a dust deflation band, with two very active spots located west-northwest from our reference site. Emissions only occur between February and June. Differences from one deflation spot to another, and from one climate state to another, are explained by analyzing the relevant meteorological and surface variables. Over most of the source region, the annual emission fluxes in the "interstadial" experiment are 30 to 50% lower than the "stadial" values; they would only be about 20% lower if the inhibition of dust uplift by the vegetation were not taken into account. Assuming that lower emissions result in reduced dust deposition leads us to the conclusion that the loess–paleosol stratigraphic succession in the Stayky

Changes in extreme regional sea surface height due to an abrupt weakening of the Atlantic meridional overturning circulation

NARCIS (Netherlands)

Brunnabend, S.-E.; Dijkstra, H. A.; Kliphuis, M. A.; van Werkhoven, B.J.C.; Bal, H. E.; Seinstra, F.; Maassen, J.; van Meersbergen, M.

2014-01-01

As an extreme scenario of dynamical sea level changes, regional sea surface height (SSH) changes that occur in the North Atlantic due to an abrupt weakening of the Atlantic meridional overturning circulation (AMOC) are simulated. Two versions of the same ocean-only model are used to study the effect

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

75 FR 74004 - Atlantic Highly Migratory Species; Advisory Panel

Science.gov (United States)

2010-11-30

... Atlantic Regional Fishery Management Councils, each of the 18 constituent states, both the U.S. Virgin... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration RIN 0648-XA059 Atlantic... nominations for the Advisory Panel (AP) for Atlantic Highly Migratory Species (HMS) Southeast Data, Assessment...

Environmental variables, algal pigments and phytoplankton in the ...

African Journals Online (AJOL)

The phytoplankton diversity, environmental variables and algal pigments of the Atlantic Ocean off the coast of Badagry, Lagos were investigated for twelve months between May 2015 and April 2016. The water chemistry characteristics reflected sea water conditions. At the two stations, the range of values recorded for some ...

75 FR 35435 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic...

Science.gov (United States)

2010-06-22

.... 100513223-0254-01] RIN 0648-AY88 Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic Deep-Sea Red Crab Specifications In- season Adjustment AGENCY: National Marine... deep-sea red crab fishery, including a target total allowable catch (TAC) and a fleet-wide days-at-sea...

Discovering where bluefin tuna, Thunnus thynnus, might go: using environmental and fishery data to map potential tuna habitat in the eastern Mediterranean Sea

OpenAIRE

Dimitrios Damalas; Persefoni Megalofonou

2012-01-01

Based on a dataset derived from commercial fisheries in the eastern Mediterranean Sea in 1998-2005, we applied generalized additive models (GAMs) to investigate the relative influence of a range of environmental factors on catch rates of Atlantic bluefin tuna (Thunnus thynnus Linnaeus, 1785). GAM analyses were conducted by separately modelling (1) the probability of making a catch (encountering a school), and (2) the positive catch rates (school size). Results suggested intra-annual variation...

Biodiversity patterns, environmental drivers and indicator species on a High-temperature Hydrothermal edifice, mid-Atlantic ridge

KAUST Repository

Sarrazin, Jozée

2015-04-25

Knowledge on quantitative faunal distribution patterns of hydrothermal communities in slow-spreading vent fields is particularly scarce, despite the importance of these ridges in the global mid-ocean system. This study assessed the composition, abundance and diversity of 12 benthic faunal assemblages from various locations on the Eiffel Tower edifice (Lucky Strike vent field, Mid-Atlantic Ridge) and investigated the role of key environmental conditions (temperature, total dissolved iron (TdFe), sulfide (TdS), copper (TdCu) and pH) on the distribution of macro- and meiofaunal species at small spatial scales (< 1 m). There were differences in macro- and meiofaunal community structure between the different sampling locations, separating the hydrothermal community of the Eiffel Tower edifice into three types of microhabitats: (1) cold microhabitats characterized by low temperatures (<6 °C), high TdCu (up to 2.4±1.37 µmol l−1), high pH (up to 7.34±0.13) but low TdS concentrations (<6.98±5.01 µmol l−1); (2) warm microhabitats characterized by warmer temperatures (>6 °C), low pH (<6.5) and high TdS/TdFe concentrations (>12.8 µmol l−1/>1.1 µmol l−1 respectively); and (3) a third microhabitat characterized by intermediate abiotic conditions. Environmental conditions showed more variation in the warm microhabitats than in the cold microhabitats. In terms of fauna, the warm microhabitats had lower macro- and meiofaunal densities, and lower richness and Shannon diversity than the cold microhabitats. Six macrofaunal species (Branchipolynoe seepensis, Amathys lutzi, Bathymodiolus azoricus, Lepetodrilus fucensis, Protolira valvatoides and Chorocaris chacei) and three meiofaunal taxa (Paracanthonchus, Cephalochaetosoma and Microlaimus) were identified as being significant indicator species/taxa of particular microhabitats. Our results also highlight very specific niche separation for copepod juveniles among the different hydrothermal microhabitats. Some sampling

Environmental sub models for a macroeconomic model: Agricultural contribution to climate change and acidification in Denmark

DEFF Research Database (Denmark)

Jensen, T.S.; Jensen, J.D.; Hasler, B.

2007-01-01

Integrated modelling of the interaction between environmental pressure and economic development is a useful tool for evaluating the progress towards sustainable development by analysing the effects on sustainability indicators of the general economic growth and implementation of national action...... economic model, environmental satellite models of energy and waste related emissions contributing to climate change and acidification. The model extension allows the main Danish contribution to climate change and acidification to be modelled. The existing model system is extended by environmental satellite...... models, in which emission coefficients are linked to economic activity variables as modelled by the agricultural sector model ESMERALDA. Agricultural emission sources related to the activity variables in ESMERALDA are mapped in order to develop the environmental satellite models and the development...

Environmental noise and noise modelling-some aspects in Malaysian development

International Nuclear Information System (INIS)

Leong, Mohd Salman; Mohd Shafiek bin Hj Yaacob

1994-01-01

Environmental noise is of growing concern in Malaysia with the increasing awareness of the need for an environmental quality consistent with improved quality of life. While noise is one of the several elements in an Environmental Impact Assessment report, the degree of emphasis in the assessment is not as thorough as other aspects in the EIA study. The measurements, prediction (if at all any), and evaluation tended to be superficial. The paper presents a summary of correct noise descriptors and annoyance assessment parameters appropriate for the evaluation of environmental noise. The paper further highlights current inadequacies in the Environmental Quality Act for noise pollution, and annoyance assessment. Some examples of local noise pollution are presented. A discussion on environmental noise modelling is presented. Examples illustrating environmental noise modelling for a mining operation and a power station are given. It is the authors' recommendation that environmental noise modelling be made mandatory in all EIA studies such that a more definitive assessment could be realised

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.)

A synthesis of the environmental response of the North and South Atlantic Sub-Tropical Gyres during two decades of AMT

Science.gov (United States)

Aiken, Jim; Brewin, Robert J. W.; Dufois, Francois; Polimene, Luca; Hardman-Mountford, Nick J.; Jackson, Thomas; Loveday, Ben; Hoya, Silvana Mallor; Dall'Olmo, Giorgio; Stephens, John; Hirata, Takafumi

2017-11-01

Anthropogenically-induced global warming is expected to decrease primary productivity in the subtropical oceans by strengthening stratification of the water column and reducing the flux of nutrients from deep-waters to the sunlit surface layers. Identification of such changes is hindered by a paucity of long-term, spatially-resolved, biological time-series data at the basin scale. This paper exploits Atlantic Meridional Transect (AMT) data on physical and biogeochemical properties (1995-2014) in synergy with a wide range of remote-sensing (RS) observations from ocean colour, Sea Surface Temperature (SST), Sea Surface Salinity (SSS) and altimetry (surface currents), combined with different modelling approaches (both empirical and a coupled 1-D Ecosystem model), to produce a synthesis of the seasonal functioning of the North and South Atlantic Sub-Tropical Gyres (STGs), and assess their response to longer-term changes in climate. We explore definitive characteristics of the STGs using data of physical (SST, SSS and peripheral current systems) and biogeochemical variables (chlorophyll and nitrate), with inherent criteria (permanent thermal stratification and oligotrophy), and define the gyre boundary from a sharp gradient in these physical and biogeochemical properties. From RS data, the seasonal cycles for the period 1998-2012 show significant relationships between physical properties (SST and PAR) and gyre area. In contrast to expectations, the surface layer chlorophyll concentration from RS data (CHL) shows an upward trend for the mean values in both subtropical gyres. Furthermore, trends in physical properties (SST, PAR, gyre area) differ between the North and South STGs, suggesting the processes responsible for an upward trend in CHL may vary between gyres. There are significant anomalies in CHL and SST that are associated with El Niño events. These conclusions are drawn cautiously considering the short length of the time-series (1998-2012), emphasising the need

The impact of the subtropical South Atlantic SST on South American precipitation

Directory of Open Access Journals (Sweden)

A. S. Taschetto

2008-11-01

Full Text Available The Community Climate Model (CCM3 from the National Center for Atmospheric Research (NCAR is used to investigate the effect of the South Atlantic sea surface temperature (SST anomalies on interannual to decadal variability of South American precipitation. Two ensembles composed of multidecadal simulations forced with monthly SST data from the Hadley Centre for the period 1949 to 2001 are analysed.

A statistical treatment based on signal-to-noise ratio and Empirical Orthogonal Functions (EOF is applied to the ensembles in order to reduce the internal variability among the integrations. The ensemble treatment shows a spatial and temporal dependence of reproducibility. High degree of reproducibility is found in the tropics while the extratropics is apparently less reproducible. Austral autumn (MAM and spring (SON precipitation appears to be more reproducible over the South America-South Atlantic region than the summer (DJF and winter (JJA rainfall. While the Inter-tropical Convergence Zone (ITCZ region is dominated by external variance, the South Atlantic Convergence Zone (SACZ over South America is predominantly determined by internal variance, which makes it a difficult phenomenon to predict. Alternatively, the SACZ over western South Atlantic appears to be more sensitive to the subtropical SST anomalies than over the continent.

An attempt is made to separate the atmospheric response forced by the South Atlantic SST anomalies from that associated with the El Niño – Southern Oscillation (ENSO. Results show that both the South Atlantic and Pacific SSTs modulate the intensity and position of the SACZ during DJF. Particularly, the subtropical South Atlantic SSTs are more important than ENSO in determining the position of the SACZ over the southeast Brazilian coast during DJF. On the other hand, the ENSO signal seems to influence the intensity of the SACZ not only in DJF but especially its oceanic branch during MAM. Both local and

Duration of effects of acute environmental changes on food anticipatory behaviour, feed intake, oxygen consumption, and cortisol release in Atlantic salmon parr.

Science.gov (United States)

Folkedal, Ole; Torgersen, Thomas; Olsen, Rolf Erik; Fernö, Anders; Nilsson, Jonatan; Oppedal, Frode; Stien, Lars H; Kristiansen, Tore S

2012-01-18

We compared behavioural and physiological responses and recovery time after different acute environmental challenges in groups of salmon parr. The fish were prior to the study conditioned to a flashing light signalling arrival of food 30 s later to study if the strength of Pavlovian conditioned food anticipatory behaviour can be used to assess how salmon parr cope with various challenges. The effect on anticipatory behaviour was compared to the effect on feed intake and physiological responses of oxygen hyper-consumption and cortisol excretion. The challenges were temperature fluctuation (6.5C° over 4 h), hyperoxia (up to 380% O(2) saturation over 4 h), and intense chasing for 10 min. Cortisol excretion was only elevated after hyperoxia and chasing, and returned to baseline levels after around 3 h or less. Oxygen hyper-consumption persisted for even shorter periods. Feed intake was reduced the first feeding after all challenges and recovered within 3 h after temperature and hyperoxia, but was reduced for days after chasing. Food anticipatory behaviour was reduced for a longer period than feed intake after hyperoxia and was low at least 6 h after chasing. Our findings suggest that a recovery of challenged Atlantic salmon parr to baseline levels of cortisol excretion and oxygen consumption does not mean full recovery of all psychological and physiological effects of environmental challenges, and emphasise the need for measuring several factors including behavioural parameters when assessing fish welfare. Copyright © 2011 Elsevier Inc. All rights reserved.

Somatic growth dynamics of West Atlantic hawksbill sea turtles: a spatio-temporal perspective

Science.gov (United States)

Bjorndal, Karen A.; Chaloupka, Milani; Saba, Vincent S.; Diez, Carlos E.; van Dam, Robert P.; Krueger, Barry H.; Horrocks, Julia A.; Santos, Armando J.B.; Bellini, Cláudio; Marcovaldi, Maria A.G.; Nava, Mabel; Willis, Sue; Godley, Brendan J.; Gore, Shannon; Hawkes, Lucy A.; McGowan, Andrew; Witt, Matthew J.; Stringell, Thomas B.; Sanghera, Amdeep; Richardson, Peter B.; Broderick, Annette C.; Phillips, Quinton; Calosso, Marta C.; Claydon, John A.B.; Blumenthal, Janice; Moncada, Felix; Nodarse, Gonzalo; Medina, Yosvani; Dunbar, Stephen G.; Wood, Lawrence D.; Lagueux, Cynthia J.; Campbell, Cathi L.; Meylan, Anne B.; Meylan, Peter A.; Burns Perez, Virginia R.; Coleman, Robin A.; Strindberg, Samantha; Guzmán-H, Vicente; Hart, Kristen M.; Cherkiss, Michael S.; Hillis-Starr, Zandy; Lundgren, Ian; Boulon, Ralf H.; Connett, Stephen; Outerbridge, Mark E.; Bolten, Alan B.

2016-01-01

Somatic growth dynamics are an integrated response to environmental conditions. Hawksbill sea turtles (Eretmochelys imbricata) are long-lived, major consumers in coral reef habitats that move over broad geographic areas (hundreds to thousands of kilometers). We evaluated spatio-temporal effects on hawksbill growth dynamics over a 33-yr period and 24 study sites throughout the West Atlantic and explored relationships between growth dynamics and climate indices. We compiled the largest ever data set on somatic growth rates for hawksbills – 3541 growth increments from 1980 to 2013. Using generalized additive mixed model analyses, we evaluated 10 covariates, including spatial and temporal variation, that could affect growth rates. Growth rates throughout the region responded similarly over space and time. The lack of a spatial effect or spatio-temporal interaction and the very strong temporal effect reveal that growth rates in West Atlantic hawksbills are likely driven by region-wide forces. Between 1997 and 2013, mean growth rates declined significantly and steadily by 18%. Regional climate indices have significant relationships with annual growth rates with 0- or 1-yr lags: positive with the Multivariate El Niño Southern Oscillation Index (correlation = 0.99) and negative with Caribbean sea surface temperature (correlation = −0.85). Declines in growth rates between 1997 and 2013 throughout the West Atlantic most likely resulted from warming waters through indirect negative effects on foraging resources of hawksbills. These climatic influences are complex. With increasing temperatures, trajectories of decline of coral cover and availability in reef habitats of major prey species of hawksbills are not parallel. Knowledge of how choice of foraging habitats, prey selection, and prey abundance are affected by warming water temperatures is needed to understand how climate change will affect productivity of consumers that live in association with coral reefs. Main

Environmental challenges and opportunities of the evolving North American electricity market : Modeling techniques and estimating environmental outcomes

International Nuclear Information System (INIS)

Patterson, Z.

2002-06-01

Background information and results of the different models publicly available used for the evaluation of environmental effects of electricity market restructuring in the various jurisdictions in North America were included in this working paper. It comprised the description of eleven models and twelve modeling exercises. The information on each model varied greatly, as it is proprietary. The models described were: (1) the Energy Information Administration's (EIA) National Energy Modeling System (NEMS), (2) the Department of Energy's Policy Office Electricity Modeling System (POEMS), (3) the Integrated Planning Model (IPM) utilized by the United States Environmental Protection Agency (US EPA), (4) Resources for the Future's (RFF) Haiku model, (5) the Canadian Energy Research Institute's Energy 2020 Model, (6) the Federal Energy Regulatory Commission's (FERC) use of ICF's Coal and Electric Utilities Model, (7) the Center for Clean Air Policy's use of General Electric's Market Assessment and Portfolio Strategies (GE MAPS) model, (8) the Center for Clean Air Policy's use of GE MAPS in combination with New Energy Associates' Proscreen II, (9) the Commission for Environmental Cooperation use of the Front of Envelope Model, (10) Ontario Power Generation's use of the Utility Fuel Economics Model and National Power Model, and (11) New York State Department of Public Service's (NYDPS) Final Generic Environmental Impact Statement using New Energy Associates' PROMOD. Also included in this working paper was a comparison of the results of models and modeling exercises on which the estimation of the environmental effects of electricity market restructuring in the United States was based. 18 refs., 5 tabs

Has Anthropogenic Forcing Caused a Discernible Change in Atlantic Hurricane Activity?

Science.gov (United States)

Knutson, T. R.; Vecchi, G. A.

2007-12-01

There is currently evidence both for and against the existence of a discernible anthropogenic impact on Atlantic hurricane activity. Emanuel's (pers. comm. 2007) Power Dissipation Index shows unprecedented high values in recent decades in the context of the past 60 yr, and correlates remarkably well with low-frequency tropical Atlantic SST variations. The limited record length, partial basin coverage by aircraft in the pre-satellite era, and lack of reconciliation with models limit the usefulness of this result for identifying possible anthropogenic influences. Landsea (EOS, 2007) uses landfalling storm statistics to infer no significant increase in basin-wide tropical storm counts since 1900. Landsea's critical assumption of a constant landfalling fraction over time limits confidence in this assessment. Nonetheless, an important finding is that U.S. landfalling hurricane activity (frequency and PDI) show no increasing trend over the past century or so. Holland and Webster (Phil. Trans. R. Soc. A 2007) conclude that basin-wide tropical cyclone and hurricane counts have increased dramatically during the past century, related to the rise in tropical Atlantic SSTs. Their key assumption is that the existing HURDAT data reliably portrays basin-wide statistics for tropical storms, hurricanes and major hurricanes, at least back to ~1900, which requires further substantiation. We use historical Atlantic ship track and storm track data to estimate the expected number of missing tropical storms each year in the pre-satellite era (1878-1965). After adjustment, the storm counts covary with tropical SSTs on multi-decadal time scales, but their long-term trend (1878-2006) is weaker than the trend in similarly normalized SSTs (though both are nominally positive). The linear trend in adjusted storm counts for 1900-2006 is strongly positive (+4.2 storms/century) and highly significant even after accounting for serial correlation. However, this trend begins near a local minimum in

Abiotic factors drives floristic variations of fern’s metacommunity in an Atlantic Forest remnant

OpenAIRE

L. E. N. Costa; R. P. Farias; A. C. P. Santiago; I. A. A. Silva; I. C. L. Barros

2018-01-01

Abstract We analyzed floristic variations in fern’s metacommunity at the local scale and their relationship with abiotic factors in an Atlantic Forest remnant of northeastern Brazil. Floristic and environmental variations were accessed on ten plots of 10 × 20 m. We performed cluster analyses, based on Bray-Curtis dissimilarity index to establish the floristic relationship. The influence of abiotic factors: luminosity, temperature, relative air humidity and relative soil moisture was evaluated...

Development and characterization of two cell lines from gills of Atlantic salmon

Science.gov (United States)

Gjessing, Mona C.; Aamelfot, Maria; Batts, William N.; Benestad, Sylvie L.; Dale, Ole B.; Thoen, Even; Weli, Simon C.; Winton, James R.

2018-01-01

Gill disease in Atlantic salmon, Salmo salar L., causes big losses in the salmon farming industry. Until now, tools to cultivate microorganisms causing gill disease and models to study the gill responses have been lacking. Here we describe the establishment and characterization of two cell lines from the gills of Atlantic salmon. Atlantic salmon gill cell ASG-10 consisted of cells staining for cytokeratin and e-cadherin and with desmosomes as seen by transmission electron microscopy suggesting the cells to be of epithelial origin. These structures were not seen in ASG-13. The cell lines have been maintained for almost 30 passages and both cell lines are fully susceptible to infection by infectious hematopoietic necrosis virus (IHNV), viral hemorrhagic septicemia virus (VHSV), infectious pancreatic necrosis virus (IPNV), Atlantic salmon reovirus TS (TSRV) and Pacific salmon paramyxovirus (PSPV). While infectious salmon anemia virus (ISAV) did not cause visible CPE, immunofluorescent staining revealed a sub-fraction of cells in both the ASG-10 and ASG-13 lines may be permissive to infection. ASG-10 is able to proliferate and migrate to close scratches in the monolayer within seven days in vitro contrary to ASG-13, which does not appear to do have the same proliferative and migratory ability. These cell lines will be useful in studies of gill diseases in Atlantic salmon and may represent an important contribution for alternatives to experimental animals and studies of epithelial–mesenchymal cell biology.

Micro-phytoplankton photosynthesis, primary production and potential export production in the Atlantic Ocean

Science.gov (United States)

Tilstone, Gavin H.; Lange, Priscila K.; Misra, Ankita; Brewin, Robert J. W.; Cain, Terry

2017-11-01

Micro-phytoplankton is the >20 μm component of the phytoplankton community and plays a major role in the global ocean carbon pump, through the sequestering of anthropogenic CO2 and export of organic carbon to the deep ocean. To evaluate the global impact of the marine carbon cycle, quantification of micro-phytoplankton primary production is paramount. In this paper we use both in situ data and a satellite model to estimate the contribution of micro-phytoplankton to total primary production (PP) in the Atlantic Ocean. From 1995 to 2013, 940 measurements of primary production were made at 258 sites on 23 Atlantic Meridional Transect Cruises from the United Kingdom to the South African or Patagonian Shelf. Micro-phytoplankton primary production was highest in the South Subtropical Convergence (SSTC ∼ 409 ± 720 mg C m-2 d-1), where it contributed between 38 % of the total PP, and was lowest in the North Atlantic Gyre province (NATL ∼ 37 ± 27 mg C m-2 d-1), where it represented 18 % of the total PP. Size-fractionated photosynthesis-irradiance (PE) parameters measured on AMT22 and 23 showed that micro-phytoplankton had the highest maximum photosynthetic rate (PmB) (∼5 mg C (mg Chl a)-1 h-1) followed by nano- (∼4 mg C (mg Chl a)-1 h-1) and pico- (∼2 mg C (mg Chl a)-1 h-1). The highest PmB was recorded in the NATL and lowest in the North Atlantic Drift Region (NADR) and South Atlantic Gyre (SATL). The PE parameters were used to parameterise a remote sensing model of size-fractionated PP, which explained 84 % of the micro-phytoplankton in situ PP variability with a regression slope close to 1. The model was applied to the SeaWiFS time series from 1998-2010, which illustrated that micro-phytoplankton PP remained constant in the NADR, NATL, Canary Current Coastal upwelling (CNRY), Eastern Tropical Atlantic (ETRA), Western Tropical Atlantic (WTRA) and SATL, but showed a gradual increase in the Benguela Upwelling zone (BENG) and South Subtropical Convergence (SSTC

Proceedings of the 2008 Atlantic Reclamation conference

Energy Technology Data Exchange (ETDEWEB)

NONE

2008-07-01

This annual event served as a forum to share information, advance knowledge, raise awareness and examine problems and solutions in the many areas of land and waterway reclamation, restoration and rehabilitation. Given the long history of resource and industrial development in Atlantic Canada, many communities are faced with the challenge of restoring contaminated sites, brownfields, and abandoned mines sites, including both underground and surface coal mines. The topics discussed at this conference ranged from mine site reclamation, brownfield redevelopment, contaminated site restoration, erosion and sediment control planning, revegetation planning, wetland and soil quality research, landuse planning, landscape design, policy, regulation and fiscal planning, environmental risk and liability insurance policies. The conference featured 14 presentations, of which 4 have been catalogued separately for inclusion in this database. tabs., figs.

MONNIE 2000: A description of a model to calculate environmental costs

International Nuclear Information System (INIS)

Hanemaaijer, A.H.; Kirkx, M.C.A.P.

2001-02-01

A new model (MONNIE 2000) was developed by the RIVM in the Netherlands in 2000 to calculate environmental costs on a macro level. The model, it's theoretical backgrounds and the technical aspects are described, making it attractive to both the user and the designer of the model. A user manual on how to calculate with the model is included. The basic principle of the model is the use of a harmonised method for calculating environmental costs, which provides the user with an output that can easily be compared with and used in other economic statistics and macro-economic models in the Netherlands. Input for the model are yearly figures on operational costs, investments and savings from environmental measures. With MONNIE 2000 calculated environmental costs per policy target group, economic sector and theme can be shown, With this model the burden of environmental measures on the economic sectors and the environmental expenditures of the government can be presented as well. MONNIE 2000 is developed in Visual Basic and by using Excel as input and output a user-friendly data exchange is realised. 12 refs

The air-sea equilibrium and time trend of hexachlorocyclohexanes in the Atlantic Ocean between the Arctic and Antarctica.

Science.gov (United States)

Lakaschus, Sonke; Weber, Kurt; Wania, Frank; Bruhn, Regina; Schrems, Otto

2002-01-15

Hexachlorocyclohexanes (HCHs) were determined simultaneously in air and seawater during two cruises across the Atlantic Ocean between the Arctic Ocean (Ny-Alesund/ Svalbard, 79 degrees N; 12 degrees E) and the Antarctic Continent (Neumayer Station/ Ekstroem Ice Shelf, 70 degrees S; 8.2 degrees W) in 1999/ 2000. The concentrations of alpha-HCH and gamma-HCH in air and surface waters of the Arctic exceeded those in Antarctica by 1-2 orders of magnitude. The gaseous concentrations of gamma-HCH were highest above the North Sea and between 20 degrees N and 30 degrees S. Fugacity fractions were used to estimate the direction of the air-sea gas exchange. These showed for alpha-HCH thatthe measured concentrations in both phases were close to equilibrium in the North Atlantic (78 degrees N-40 degrees N), slightly undersaturated between 30 degrees N and 10 degrees S and again close to equilibrium between 20 degrees S and 50 degrees S. Y-HCH has reached phase equilibrium in the North Atlantic as alpha-HCH, but the surface waters of the tropical and southern Atlantic were strongly undersaturated with y-HCH, especially between 30 degrees N and 20 degrees S. These findings are significantly different from two earlier estimates around 1990 as a result of global emission changes within the past decade. Therefore, we investigated the time trend of the HCHs in the surface waters of the Atlantic between 50 degrees N and 60 degrees S on the basis of archived samples taken in 1987-1997 and those from 1999. A decrease of alpha-HCH by a factor of approximately 4 is observed at all sampling locations. No decrease of gamma-HCH occurred between 30 degrees N and 30 degrees S, but there was a decrease in the North Atlantic, North Sea, and in the South Atlantic south of 40 degrees S. The constant level of gamma-HCH in the tropical Atlantic confirms the conclusion that the tropical Atlantic acts as a sink for y-HCH at present time. The measured alpha-HCH seawater concentrations were compared

Model to Evaluate Pro-Environmental Consumer Practices

Directory of Open Access Journals (Sweden)

Wendolyn Aguilar-Salinas

2017-02-01

Full Text Available The consumer plays a key role in resource conservation; therefore, it is important to know consumer behavior to identify consumer profiles and to promote pro-environmental practices in society that encourage resource conservation and reductions in waste generation. The purpose of this paper is to implement a fuzzy model to evaluate consumer behavior in relation to three pro-environmental practices that can be implemented at the household level, including reductions in resource consumption (reduce, reuse of resources (reuse, and recycling (recycle. To identify socio-demographic profiles that characterize an environmentally responsible consumer, 2831 surveys were applied on a representative sample of consumers residing in a Mexican city. Fuzzy logic and neural networks were applied using a Sugeno-type subtractive clustering to determine each profile. The model input variables were socioeconomic status, age, education level, monthly income, occupation and the type of organizations with which the consumer is affiliated. The output variables were represented by pro-environmental practices. Results show that the consumer practices are performed independently of each other, with the most frequent pro-environmental consumer practices being reduction and reuse.

Changes in the interannual variability of the tropical Pacific as a response to an equatorial Atlantic forcing

Directory of Open Access Journals (Sweden)

Marta Martín-Rey

2012-09-01

Full Text Available Previous studies have reported that the tropical Atlantic has had an influence on tropical Pacific interannual variability since the 1970s. This variability is studied in the present work, using simulations from a coupled model in the Indo-Pacific but with observed sea surface temperature (SST prescribed over the Atlantic. The interannual variability is compared with that from a control simulation in which climatological SSTs are prescribed over the Atlantic. Differences in the Pacific mean state and in its variability are found in the forced simulation as a response to a warming in the equatorial Atlantic, characterized by a cooler background state and an increase in the variability over the tropical Pacific. A striking result is that the principal modes of tropical Pacific SST interannual variability show significant differences before and after the 1970s, providing new evidence of the Atlantic influence on the Pacific Ocean. Significant cooling (warming in the equatorial Atlantic could have caused anomalous winds in the central-easter Pacific during the summer since 1970s. The thermocline depth also seems to be altered, triggering the dynamical processes involved in the development of El Niño (La Niña phenomenon in the following winter. An increase in frequency of Niño and Niña events favouring the Central Pacific (CP ones is observed in the last three decades. Further analyses using coupled models are still necessary to help us to understand the causes of this inter-basin connection.

Status report on geochemical field results from Atlantic study sites

International Nuclear Information System (INIS)

Wilson, T.R.S.; Thomson, J.; Hydes, D.J.; Colley, S.

1983-01-01

This report summarises the results of preliminary geochemical investigations at three North Atlantic study areas. The two eastern sites, on the Cape Verde abyssal plain (CV2) and east of Great Meteor Seamount (GME) were visited during 1982. The results presented are preliminary. Studies in the western Atlantic, close to the Nares Abyssal Plain study site are more detailed and are presented in a separate paper. The report shows for the first time the relative redox status of the three sites. The differences are unexpectedly large, the most reduced cores being recovered at GME and the most oxidised at CV2. The sporadic nature of Recent sediment accumulation at these sites is also emphasised. In order to place these preliminary results in context their relevance to the production of mathematical system models is discussed in a closing section. The necessity for such models to rest on sound foundations of geochemical understanding is noted. Suggestions on future research priorities are offered for discussion. (author)

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

The use of models to assess environmental impacts

International Nuclear Information System (INIS)

Gustafson, P.F.

1978-01-01

Environmental impacts will include the effects on man as well as on other major segments of the natural or indigenous ecosystems. In their present state of development, the models used for environmental impact analysis give at least a semiquantitative estimate of the magnitude of such impacts. The methods used in the development of models are given, and their strengths and weaknesses are described. The relationship between predictive, before-the-fact models, and monitoring programs conducted during facility operation are also discussed

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

STABILITY OF INTERNATIONAL ENVIRONMENTAL AGREEMENTS IN LEADERSHIP MODEL

Institute of Scientific and Technical Information of China (English)

Jin ZHANG; Shouyang WANG; Lei ZU

2008-01-01

International Environmental Agreements (IEAs) are a form of cooperation ratified by countries which can improve the management of shared environmental resources. The authors analyze the stability of International Environmental Agreements in leadership model. In 2006, Diamantoudi & Sartzetakis found that a stable coalition consists of either 2, 3, or 4 members if the number of countries is greater than 4. Their model is reconsidered. It is shown that the size of stable IEAs decreases from 3 to 2 when the total number of countries involved increases. However, a situation that can guarantee 4 to be the size of stable IEAs could not be found.

Analysis of a general circulation model. II - Distribution of kinetic energy in the South Atlantic and Kuroshio/Oyashio systems

Science.gov (United States)

Garraffo, Zulema; Garzoli, Silvia L.; Haxby, William; Olson, Donald

1992-01-01

It was found (Garzoli et al., 1992) that the general circulation model of Semtner and Chervin (1992) provides accurate descriptions of the Brazil-Malvinas and the Kuroshio/Oyashio confluence systems, except for the fact that the model prediction shows less variability than that present in observations. This paper investigates the problem of model variability by analyzing the mean and the eddy kinetic energy from the model and comparing the values with the Geosat altimeter observations for the South Atlantic Ocean and for the Kuroshio system. It is found that, while the model shows transient eddy activity in the areas that overlap the Geosat observations, the energy level of the model transient motions is considerably smaller following an arch along the bottom topography. The same was found from the comparisons made with values obtained from FGGE and surface drifters. It is suggested that the model is poorly resolving instabilities in the confluence front, and is not resolving other transients appearing in regions of marked topography.

Specification and Aggregation Errors in Environmentally Extended Input-Output Models

NARCIS (Netherlands)

Bouwmeester, Maaike C.; Oosterhaven, Jan

This article considers the specification and aggregation errors that arise from estimating embodied emissions and embodied water use with environmentally extended national input-output (IO) models, instead of with an environmentally extended international IO model. Model specification errors result

Coccolithophore export production and seasonal variation from a trans-Atlantic array of sediment trap moorings (NW Africa to Caribbean)

Science.gov (United States)

Guerreiro, C. V.; Baumann, K. H.; Brummer, G. J. A.; Fischer, G.; Korte, L.; Stuut, J. B. W.

2016-02-01

In this study, we contribute to disclose the ecology and seasonal variability of coccolithophores, to improve their use as proxies for environmental variability in the Equatorial Atlantic Ocean. To this aim, the coccolithophore export fluxes and species composition were investigated from a trans-Atlantic array of sediment trap moorings from NW Africa (Cape Blanc) into the Caribbean (Barbados) (i.e., CB at 20°N/52ºW: M1 at 12ºN/23ºW; M2 at 14ºN/37ºW; M4 at 12ºN/49ºW). Each of the sediment trap devices was deployed at 1200 m depth, sampling settling particles at two-week intervals, and covering a full year (Oct. 2012 to Oct. 2013). First results show important contrasts between both ends of the trans-Atlantic array: total coccolith fluxes were much higher in the oligotrophic station M4 (western part of the basin) than in the highly productive waters off Cape Blanc (eastern edge of the basin), mostly due to the overwhelming dominance of the deep photic layer species Florisphaera profunda and Gladiolithus flabellatus. Off Cape Blanc, higher abundances of the placolith-bearing species Emiliania huxleyi and Gephyrocapsa spp. were found, more typical of the upper photic layer, while F. profunda decreases in relative abundance and G. flabellatus is almost absent, in comparison to M4. The presence of trans-Atlantic ecological gradients in terms of species diversity and prevalence of K- and r-selected species will be discussed with respect to the prevailing environmental conditions during the monitored period, including Saharan-dust deposition and the influence of the Amazon River plume.This study is part of ongoing multidisciplinary research in the study area, in the context of the projects "DUSTRAFFIC" and "TRAFFIC - Transatlantic Fluxes of Saharan Dust".

Model Fusion Tool - the Open Environmental Modelling Platform Concept

Science.gov (United States)

Kessler, H.; Giles, J. R.

2010-12-01

The vision of an Open Environmental Modelling Platform - seamlessly linking geoscience data, concepts and models to aid decision making in times of environmental change. Governments and their executive agencies across the world are facing increasing pressure to make decisions about the management of resources in light of population growth and environmental change. In the UK for example, groundwater is becoming a scarce resource for large parts of its most densely populated areas. At the same time river and groundwater flooding resulting from high rainfall events are increasing in scale and frequency and sea level rise is threatening the defences of coastal cities. There is also a need for affordable housing, improved transport infrastructure and waste disposal as well as sources of renewable energy and sustainable food production. These challenges can only be resolved if solutions are based on sound scientific evidence. Although we have knowledge and understanding of many individual processes in the natural sciences it is clear that a single science discipline is unable to answer the questions and their inter-relationships. Modern science increasingly employs computer models to simulate the natural, economic and human system. Management and planning requires scenario modelling, forecasts and ‘predictions’. Although the outputs are often impressive in terms of apparent accuracy and visualisation, they are inherently not suited to simulate the response to feedbacks from other models of the earth system, such as the impact of human actions. Geological Survey Organisations (GSO) are increasingly employing advances in Information Technology to visualise and improve their understanding of geological systems. Instead of 2 dimensional paper maps and reports many GSOs now produce 3 dimensional geological framework models and groundwater flow models as their standard output. Additionally the British Geological Survey have developed standard routines to link geological

How Participatory Should Environmental Governance Be? Testing the Applicability of the Vroom-Yetton-Jago Model in Public Environmental Decision-Making

Science.gov (United States)

Lührs, Nikolas; Jager, Nicolas W.; Challies, Edward; Newig, Jens

2018-02-01

Public participation is potentially useful to improve public environmental decision-making and management processes. In corporate management, the Vroom-Yetton-Jago normative decision-making model has served as a tool to help managers choose appropriate degrees of subordinate participation for effective decision-making given varying decision-making contexts. But does the model recommend participatory mechanisms that would actually benefit environmental management? This study empirically tests the improved Vroom-Jago version of the model in the public environmental decision-making context. To this end, the key variables of the Vroom-Jago model are operationalized and adapted to a public environmental governance context. The model is tested using data from a meta-analysis of 241 published cases of public environmental decision-making, yielding three main sets of findings: (1) The Vroom-Jago model proves limited in its applicability to public environmental governance due to limited variance in its recommendations. We show that adjustments to key model equations make it more likely to produce meaningful recommendations. (2) We find that in most of the studied cases, public environmental managers (implicitly) employ levels of participation close to those that would have been recommended by the model. (3) An ANOVA revealed that such cases, which conform to model recommendations, generally perform better on stakeholder acceptance and environmental standards of outputs than those that diverge from the model. Public environmental management thus benefits from carefully selected and context-sensitive modes of participation.

Atlantic CFC data in CARINA

Directory of Open Access Journals (Sweden)

R. Steinfeldt

2010-01-01

Full Text Available Water column data of carbon and carbon-relevant parameters have been collected and merged into a new database called CARINA (CARbon IN the Atlantic. In order to provide a consistent data set, all data have been examined for systematic biases and adjusted if necessary (secondary quality control (QC. The CARINA data set is divided into three regions: the Arctic/Nordic Seas, the Atlantic region and the Southern Ocean. Here we present the CFC data for the Atlantic region, including the chlorofluorocarbons CFC-11, CFC-12 and CFC-113 as well as carbon tetrachloride (CCl₄. The methods applied for the secondary quality control, a crossover analyses, the investigation of CFC ratios in the ocean and the CFC surface saturation are presented. Based on the results, the CFC data of some cruises are adjusted by a certain factor or given a "poor'' quality flag.

Evaluation of the Holocene environmental changes of the southwest ...

Indian Academy of Sciences (India)

the palaeo-environmental conditions of western coast of India during this epoch through the analysis of ... India had experienced high intensity rainfall during the earlier part of the Atlantic chronozone due to ..... of evergreen forest elements in pollen spectra also .... Quaternary peat deposits from Vembanad Lake (lagoon),.

A mathematical model for environmental risk assessment in manufacturing industry

Institute of Scientific and Technical Information of China (English)

何莉萍; 徐盛明; 陈大川; 党创寅

2002-01-01

Environmental conscious manufacturing has become an important issue in industry because of market pressure and environmental regulations. An environmental risk assessment model was developed based on the network analytic method and fuzzy set theory. The "interval analysis method" was applied to deal with the on-site monitoring data as basic information for assessment. In addition, the fuzzy set theory was employed to allow uncertain, interactive and dynamic information to be effectively incorporated into the environmental risk assessment. This model is a simple, practical and effective tool for evaluating the environmental risk of manufacturing industry and for analyzing the relative impacts of emission wastes, which are hazardous to both human and ecosystem health. Furthermore, the model is considered useful for design engineers and decision-maker to design and select processes when the costs, environmental impacts and performances of a product are taken into consideration.

Uptake of uranium in Atlantic salmon gills following exposure experiments demonstrated by SR-XRF tomography

Energy Technology Data Exchange (ETDEWEB)

Lind, O.C.; Cagno, S.; Brit Salbu, H.C.T. [Centre of Excellence in Environmental Radioactivity - CERAD, Norwegian University of Life Sciences - UMB (Norway); Vanmeert, F.; Nuyts, G.; Janssens, K. [University of Antwerp (Belgium); Alfeld, M.; Falkenberg, G. [Deutsches Elektronen-Synchrotron - DESY (Germany)

2014-07-01

Uranium is a naturally occurring radionuclide as well as a heavy metal that can be found in elevated concentrations (mg/L) in the aquatic environment and therefore may pose a risk to aquatic organisms including fish. The major challenges in monitoring the fate of U in complex media, such as soils, sediments and water are to identify mobile and bioavailable U species, interactions with environmental components, transfer to organisms via sorption to surfaces and across membranes, and the internal distribution of target organs. As part of a larger study, U accumulation in gills and internal organs (e.g. liver) as well as mortality of Atlantic Salmon (Salmo salar) were studied as a function of U concentration as well as pH of the exposure water. As Atlantic salmon does not ingest freshwater, the major pathway for uptake of U in the liver is hypothesized to be by transfer across the gills. However, to our best knowledge, active uptake of U within gill filaments has never been proven. In the present work, we demonstrate that following 96 hours exposure of 6 mg U/l in freshwater at pH 7 and 1 mg U/l at pH 5, U was actively taken up in the Atlantic Salmon gill filaments. The internal distribution of U within exposed organisms was visualized using μXRF/μXRD two-dimensional scanning and XRF/XRD tomography at the microprobe end-station of the PETRA III P06 beamline. The recently developed and highly efficient Maia detector array was successfully employed to record extended high-resolution element-specific maps of the tissue samples. First, conventional 2D μXRF/μXRD mapping allowed to identify the axial planes in the samples actually containing U. On the same samples, higher resolution virtual cross-sections were obtained (18 keV, 0.6 μm beam size) by means of μXRF/μXRD tomography of the planes in which U was encountered. The results proved that U not only adheres to the external boundary of the fish gills, but it is also taken up via gills. The results of this work