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  • Other Sources  (198)
  • AMS (American Meteorological Society)  (82)
  • Kluwer  (67)
  • Nature Publishing Group  (36)
  • American Chemical Society
  • American Institute of Physics (AIP)
  • American Society of Hematology
  • Macmillian Magazines Ltd.
  • 2000-2004  (198)
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  • 1
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    Kluwer
    In:  Orlando, Florida, Kluwer, vol. 27, pp. 559-932, (1-4020-2401-0, 792 pp.)
    Publication Date: 2004
    Keywords: Proceedings of a conference ; Tomography ; Acoustics ; Seismology ; Seismics (controlled source seismology) ; Textbook of physics ; Textbook of geophysics ; Textbook of mathematics
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  • 2
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    Kluwer
    In:  Dordrecht, 344 pp., Kluwer, vol. 20, no. Publ. No. 12, pp. 81-89, (ISBN 1-4020-1267-5 (hb), ISBN 1-4020-1268-3 (pb))
    Publication Date: 2004
    Keywords: Textbook of geophysics ; NOModelling ; GeodesyY ; Crustal deformation (cf. Earthquake precursor: deformation or strain) ; post-glacial ; Rheology ; Earth rotation ; Inelastic ; Seismology ; earth mantle ; post-seismic ; Dislocation
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  • 3
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    Kluwer
    In:  Dordrecht, 368 pp., Kluwer, vol. V/1, subvol. b, pp. 559-932, (ISBN: 1-4020-1827-4)
    Publication Date: 2004
    Keywords: Earthquake engineering, engineering seismology ; Textbook of geophysics ; Textbook of engineering ; Earthquake risk ; Site amplification ; vulnerability ; microzonation ; Earthquake hazard ; CD-Rom
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  • 4
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    AMS (American Meteorological Society)
    In:  Journal of Climate, 17 (19). pp. 3761-3774.
    Publication Date: 2017-08-23
    Description: The decadal-scale variability in the tropical Pacific has been analyzed herein by means of observations and numerical model simulations. The two leading modes of the sea surface temperature (SST) variability in the central western Pacific are a decadal mode with a period of about 10 yr and the ENSO mode with a dominant period of about 4 yr. The SST anomaly pattern of the decadal mode is ENSO like. The decadal mode, however, explains most variance in the western equatorial Pacific and off the equator. A simulation with an ocean general circulation model (OGCM) forced by reanalysis data is used to explore the origin of the decadal mode. It is found that the variability of the shallow subtropical–tropical overturning cells is an important factor in driving the decadal mode. This is supported by results from a multicentury integration with a coupled ocean–atmosphere general circulation model (CGCM) that realistically simulates tropical Pacific decadal variability. Finally, the sensitivity of the shallow subtropical–tropical overturning cells to greenhouse warming is discussed by analyzing the results of a scenario integration with the same CGCM.
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  • 5
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 34 . pp. 817-843.
    Publication Date: 2020-08-04
    Description: The current system east of the Grand Banks was intensely observed by World Ocean Circulation Experiment (WOCE) array ACM-6 during 1993–95 with eight moorings, reaching about 500 km out from the shelf edge and covering the water column from about 400-m depth to the bottom. More recently, a reduced array by the Institut für Meerskunde (IfM) at Kiel, Germany, of four moorings was deployed during 1999–2001, focusing on the deep-water flow near the western continental slope. Both sets of moored time series, each about 22 months long, are combined here for a mean current boundary section, and both arrays are analyzed for the variability of currents and transports. A mean hydrographic section is derived from seven ship surveys and is used for geostrophic upper-layer extrapolation and isopycnal subdivision of the mean transports into deep-water classes. The offshore part of the combined section is dominated by the deep-reaching North Atlantic Current (NAC) with currents still at 10 cm s−1 near the bottom and a total northward transport of about 140 Sv (Sv ≡ 106 m3 s−1), with the details depending on the method of surface extrapolation used. The mean flow along the western boundary was southward with the section-mean North Atlantic Deep Water outflow determined to be 12 Sv below the σθ = 27.74 kg m−3 isopycnal. However, east of the deep western boundary current (DWBC), the deep NAC carries a transport of 51 Sv northward below σθ = 27.74 kg m−3, resulting in a large net northward flow in the western part of the basin. From watermass signatures it is concluded that the deep NAC is not a direct recirculation of DWBC water masses. Transport time series for the DWBC variability are derived for both arrays. The variance is concentrated in the period range from 2 weeks to 2 months, but there are also variations at interannual and longer periods, with much of the DWBC variability being related to fluctuations and meandering of the NAC. A significant annual cycle is not recognizable in the combined current and transport time series of both arrays. The moored array results are compared with other evidence on deep outflow and recirculation, including recent models of different types and complexity.
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  • 6
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    AMS (American Meteorological Society)
    In:  Journal of Climate, 17 (22). pp. 4301-4315.
    Publication Date: 2020-08-04
    Description: Simulations and seasonal forecasts of tropical Pacific SST and subsurface fields that are based on the global Consortium for Estimating the Circulation and Climate of the Ocean (ECCO) ocean-state estimation procedure are investigated. As compared to similar results from a traditional ENSO simulation and forecast procedure, the hindcast of the constrained ocean state is significantly closer to observed surface and subsurface conditions. The skill of the 12-month lead SST forecast in the equatorial Pacific is comparable in both approaches. The optimization appears to have better skill in the SST anomaly correlations, suggesting that the initial ocean conditions and forcing corrections calculated by the ocean-state estimation do have a positive impact on the predictive skill. However, the optimized forecast skill is currently limited by the low quality of the statistical atmosphere. Progress is expected from optimizing a coupled model over a longer time interval with the coupling statistics being part of the control vector.
    Type: Article , PeerReviewed
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  • 7
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 34 (11). pp. 2398-2412.
    Publication Date: 2020-08-04
    Description: In the eastern South Pacific Ocean, at a depth of about 200 m, a salinity minimum is found. This minimum is associated with a particular water mass, the “Shallow Salinity Minimum Water” (SSMW). SSMW outcrops in a fresh tongue (Smin) centered at about 45°S. The Smin appears to emanate from the eastern boundary, against the mean flow. The watermass transformation that creates SSMW and Smin is investigated here. The Smin and SSMW are transformed from saltier and warmer waters originating from the western South Pacific. The freshening and cooling occur when the water is advected eastward at the poleward side of the subtropical gyre. Sources of freshening and cooling are air–sea exchange and advection of water from south of the subtropical gyre. A freshwater and heat budget for the mixed layer reveals that both sources equally contribute to the watermass transformation in the mixed layer. The freshened and cooled mixed layer water is subducted into the gyre interior along the southern rim of the subtropical gyre. Subduction into the zonal flow restricts the transformation of interior properties to diffusion only. A simple advection/diffusion balance reveals diffusion coefficients of order 2000 m2 s−1. The tongue shape of the Smin is explained from a dynamical viewpoint because no relation to a positive precipitation–evaporation balance was found. Freshest Smin values are found to coincide with slowest eastward mixed layer flow that accumulates the largest amounts of freshwater in the mixed layer and creates the fresh tongue at the sea surface. Although the SSMW is the densest and freshest mode of water subducted along the South American coast, the freshening and cooling in the South Pacific affect a whole range of densities (25.0–26.8 kg m−3). The transformed water turns northward with the gyre circulation and contributes to the hydrographic structure of the gyre farther north. Because the South Pacific provides most of the source waters that upwell along the equatorial Pacific, variability in South Pacific hydrography may influence equatorial Pacific hydrography. Because one-half of the transformation is found to be controlled through Ekman transport, variability in wind forcing at the southern rim of the subtropical gyre may be a source for variability of the equatorial Pacific.
    Type: Article , PeerReviewed
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  • 8
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 34 (1). pp. 293-305.
    Publication Date: 2018-04-11
    Description: An analytical model is developed to study the tidally induced mean circulation in the frontal zone. Four distinct forcing mechanisms are identified, which result in the generation of the counterclockwise Bernoulli cell, the clockwise Ekman cell, the clockwise frontal cell, and the Stokes drift (facing in the direction with the shallow water to the left). The decomposition of the cross-frontal circulation provides a dynamical framework for interpreting and understanding its complex structure. To illustrate the underlying physics, three model configurations are considered pertaining to a homogenous ocean and winter and summer fronts. For a homogeneous ocean, the circulation is dominated by three cells; for the winter front, the offshore Bernoulli cell is strengthened; and for the summer front, two counterrotating cells are found in the vertical direction, associated with the two branches of the front. The dependence of the cell structure on the Ekman, Burger, and other dimensionless numbers is examined.
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  • 9
    Publication Date: 2016-09-07
    Description: A multi-model ensemble-based system for seasonal-to-interannual prediction has been developed in a joint European project known as DEMETER (Development of a European Multimodel Ensemble Prediction System for Seasonal to Interannual Prediction). The DEMETER system comprises seven global atmosphere–ocean coupled models, each running from an ensemble of initial conditions. Comprehensive hindcast evaluation demonstrates the enhanced reliability and skill of the multimodel ensemble over a more conventional single-model ensemble approach. In addition, innovative examples of the application of seasonal ensemble forecasts in malaria and crop yield prediction are discussed. The strategy followed in DEMETER deals with important problems such as communication across disciplines, downscaling of climate simulations, and use of probabilistic forecast information in the applications sector, illustrating the economic value of seasonal-to-interannual prediction for society as a whole.
    Type: Article , PeerReviewed
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  • 10
    Publication Date: 2020-08-04
    Description: This study focuses on an important aspect of air–sea interaction in models, namely, large-scale, spurious heat fluxes due to false pathways of the Gulf Stream and North Atlantic Current (NAC) in the “storm formation region” south and east of Newfoundland. Although high-resolution eddy-resolving models show some improvement in this respect, results are sensitive to poorly understood, subgrid-scale processes for which there is currently no complete, physically based parameterization. A simple method to correct an ocean general circulation model (OGCM), acting as a practical substitute for a physically based parameterization, is explored: the recently proposed “semiprognostic method,” a technique for adiabatically adjusting flow properties of a hydrostatic OGCM. The authors show that application of the method to an eddy-permitting model of the North Atlantic Ocean yields more realistic flow patterns and watermass characteristics in the Gulf Stream and NAC regions; in particular, spurious surface heat fluxes are reduced. Four simple modifications to the method are proposed, and their benefits are demonstrated. The modifications successfully account for three drawbacks of the original method: reduced geostrophic wave speeds, damped mesoscale eddy activity, and spurious interaction with topography. It is argued that use of a corrected (eddy permitting) OGCM in a coupled modeling system for simulating present climate (as now becomes possible because of increasing computer power) should lead to a more realistic simulation in regions of strong air–sea interaction as compared with that obtained with an uncorrected model. The method is also well suited for the simulation of the uptake and transport of passive tracers, such as anthropogenic carbon dioxide or components of ecosystem models.
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  • 11
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    Nature Publishing Group
    In:  Nature Reviews Microbiology, 2 (5). pp. 414-424.
    Publication Date: 2020-06-23
    Description: Horizontal gene transfer is an important mechanism for the evolution of microbial genomes. Pathogenicity islands — mobile genetic elements that contribute to rapid changes in virulence potential — are known to have contributed to genome evolution by horizontal gene transfer in many bacterial pathogens. Increasing evidence indicates that equivalent elements in non-pathogenic species — genomic islands — are important in the evolution of these bacteria, influencing traits such as antibiotic resistance, symbiosis and fitness, and adaptation in general. This review discusses the recent lessons that have been learned from pathogenicity islands in pathogenic microorganisms and how they apply to the role of genomic islands in commensal, symbiotic and environmental bacteria.
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  • 12
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 34 (3). pp. 566-581.
    Publication Date: 2020-08-04
    Description: Two major water masses dominate the deep layers in the Mariana and Caroline Basins: the Lower Circumpolar Water (LCPW), arriving from the Southern Ocean along the slopes north of the Marshall Islands, and the North Pacific Deep Water (NPDW) reaching the region from the northeastern Pacific Ocean. Hydrographic and moored observations and multibeam echosounding were performed in the East Mariana and the East Caroline Basins to detail watermass distributions and flow paths in the area. The LCPW enters the East Mariana Basin from the east. At about 13°N, however, in the southern part of the basin, a part of this water mass arrives in a southward western boundary flow along the Izu–Ogasawara–Mariana Ridge. Both hydrographic observations and moored current measurements lead to the conclusion that this water not only continues westward to the West Mariana Basin as suggested before, but also provides bottom water to the East Caroline Basin. The critical throughflow regions were identified by multibeam echosounding at the Yap Mariana Junction between the East and West Mariana Basins and at the Caroline Ridge between the East Mariana and East Caroline Basins. The throughflow is steady between the East and West Mariana Basins, whereas more variability is found at the Caroline Ridge. At both locations, throughflow fluctuations are correlated with watermass property variations suggesting layer-thickness changes. The total transport to the two neighboring basins is only about 1 Sverdrup (1Sv ≡ 106 m3 s−1) but has considerable impact on the watermass structure in these basins. Estimates are given for the diapycnal mixing that is required to balance the inflow into the East Caroline Basin. Farther above in the water column, the high-silica tongue of NPDW extends from the east to the far southwestern corner of the East Mariana Basin, with transports being mostly southward across the basin.
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  • 13
    Publication Date: 2017-03-09
    Description: The existence in the ocean of deep western boundary currents, which connect the high-latitude regions where deep water is formed with upwelling regions as part of the global ocean circulation, was postulated more than 40 years ago1. These ocean currents have been found adjacent to the continental slopes of all ocean basins, and have core depths between 1,500 and 4,000 m. In the Atlantic Ocean, the deep western boundary current is estimated to carry (10–40) times 106 m3 s-1 of water2, 3, 4, 5, transporting North Atlantic Deep Water—from the overflow regions between Greenland and Scotland and from the Labrador Sea—into the South Atlantic and the Antarctic circumpolar current. Here we present direct velocity and water mass observations obtained in the period 2000 to 2003, as well as results from a numerical ocean circulation model, showing that the Atlantic deep western boundary current breaks up at 8° S. Southward of this latitude, the transport of North Atlantic Deep Water into the South Atlantic Ocean is accomplished by migrating eddies, rather than by a continuous flow. Our model simulation indicates that the deep western boundary current breaks up into eddies at the present intensity of meridional overturning circulation. For weaker overturning, continuation as a stable, laminar boundary flow seems possible.
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  • 14
    Publication Date: 2020-08-04
    Description: Sea surface temperature (SST) observations in the North Atlantic indicate the existence of strong multidecadal variability with a unique spatial structure. It is shown by means of a new global climate model, which does not employ flux adjustments, that the multidecadal SST variability is closely related to variations in the North Atlantic thermohaline circulation (THC). The close correspondence between the North Atlantic SST and THC variabilities allows, in conjunction with the dynamical inertia of the THC, for the prediction of the slowly varying component of the North Atlantic climate system. It is shown additionally that past variations of the North Atlantic THC can be reconstructed from a simple North Atlantic SST index and that future, anthropogenically forced changes in the THC can be easily monitored by observing SSTs. The latter is confirmed by another state-of-the-art global climate model. Finally, the strong multidecadal variability may mask an anthropogenic signal in the North Atlantic for some decades.
    Type: Article , PeerReviewed
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  • 15
    Publication Date: 2017-08-18
    Description: A systematic modular approach to investigate the respective roles of the ocean and atmosphere in setting El Niño characteristics in coupled general circulation models is presented. Several state-of-the-art coupled models sharing either the same atmosphere or the same ocean are compared. Major results include 1) the dominant role of the atmosphere model in setting El Niño characteristics (periodicity and base amplitude) and errors (regularity) and 2) the considerable improvement of simulated El Niño power spectratoward lower frequencywhen the atmosphere resolution is significantly increased. Likely reasons for such behavior are briefly discussed. It is argued that this new modular strategy represents a generic approach to identifying the source of both coupled mechanisms and model error and will provide a methodology for guiding model improvement.
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  • 16
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 34 . pp. 772-792.
    Publication Date: 2018-04-11
    Description: The Indonesian Throughflow (ITF) spreading pathways and time scales in the Indian Ocean are investigated using both observational data and two numerical tracer experiments, one being a three-dimensional Lagrangian trajectory experiment and the other a transit-time probability density function (PDF) tracer experiment, in an ocean general circulation model. The model climatology is in agreement with observations and other model results except that speeds of boundary currents are lower. Upon reaching the western boundary within the South Equatorial Current (SEC), the trajectories of the ITF tracers within the thermocline exhibit bifurcation. The Lagrangian trajectory experiment shows that at the western boundary about 38%±5% thermocline ITF water flows southward to join the Agulhas Current, consequently exiting the Indian Ocean, and the rest, about 62%±5%, flows northward to the north of SEC. In boreal summer, ITF water penetrates into the Northern Hemisphere within the Somali Current. The primary spreading pathway of the thermocline ITF water north of SEC is upwelling to the surface layer with subsequent advection southward within the surface Ekman layer toward the southern Indian Ocean subtropics. There it is subducted and advected northward in the upper thermocline to rejoin the SEC. Both the observations and the trajectory experiment suggest that the upwelling occurs mainly along the coast of Somalia during boreal summer and in the open ocean within a cyclonic gyre in the Tropics south of the equator throughout the year. All the ITF water eventually exits the Indian Ocean along the western boundary within the Mozambique Channel and the east coast of Madagascar and, farther south, the Agulhas Current region. The advective spreading time scales, represented by the elapsed time corresponding to the maximum of transit- time PDF, show that in the upper thermocline the ITF crosses the Indian Ocean, from the Makassar Strait to the east coast of the African continent, on a time scale of about 10 yr and reaches the Arabian Sea on a time scale of over 20 yr.
    Type: Article , PeerReviewed
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  • 17
    Publication Date: 2017-03-07
    Description: The climate of the last glacial period was extremely variable, characterized by abrupt warming events in the Northern Hemisphere, accompanied by slower temperature changes in Antarctica and variations of global sea level. It is generally accepted that this millennial-scale climate variability was caused by abrupt changes in the ocean thermohaline circulation. Here we use a coupled ocean–atmosphere–sea ice model to show that freshwater discharge into the North Atlantic Ocean, in addition to a reduction of the thermohaline circulation, has a direct effect on Southern Ocean temperature. The related anomalous oceanic southward heat transport arises from a zonal density gradient in the subtropical North Atlantic caused by a fast wave-adjustment process. We present an extended and quantitative bipolar seesaw concept that explains the timing and amplitude of Greenland and Antarctic temperature changes, the slow changes in Antarctic temperature and its similarity to sea level, as well as a possible time lag of sea level with respect to Antarctic temperature during Marine Isotope Stage 3.
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  • 18
    Publication Date: 2017-03-10
    Description: The role of iron in enhancing phytoplankton productivity in high nutrient, low chlorophyll oceanic regions was demonstrated first through iron-addition bioassay experiments1 and subsequently confirmed by large-scale iron fertilization experiments2. Iron supply has been hypothesized to limit nitrogen fixation and hence oceanic primary productivity on geological timescales3, providing an alternative to phosphorus as the ultimate limiting nutrient4. Oceanographic observations have been interpreted both to confirm and refute this hypothesis5, 6, but direct experimental evidence is lacking7. We conducted experiments to test this hypothesis during the Meteor 55 cruise to the tropical North Atlantic. This region is rich in diazotrophs8 and strongly impacted by Saharan dust input9. Here we show that community primary productivity was nitrogen-limited, and that nitrogen fixation was co-limited by iron and phosphorus. Saharan dust addition stimulated nitrogen fixation, presumably by supplying both iron and phosphorus10, 11. Our results support the hypothesis that aeolian mineral dust deposition promotes nitrogen fixation in the eastern tropical North Atlantic.
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  • 19
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    Nature Publishing Group
    In:  Nature, 429 .
    Publication Date: 2017-03-10
    Description: No need to wait for more information: industrialized fishing is already wiping out stocks.
    Type: Article , NonPeerReviewed
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  • 20
    Publication Date: 2019-09-23
    Description: The formation and sinking of biogenic particles mediate vertical mass fluxes and drive elemental cycling in the ocean1. Whereas marine sciences have focused primarily on particle production by phytoplankton growth, particle formation by the assembly of organic macromolecules has almost been neglected2, 3. Here we show, by means of a combined experimental and modelling study, that the formation of polysaccharide particles is an important pathway to convert dissolved into particulate organic carbon during phytoplankton blooms, and can be described in terms of aggregation kinetics. Our findings suggest that aggregation processes in the ocean cascade from the molecular scale up to the size of fast-settling particles, and give new insights into the cycling and export of biogeochemical key elements such as carbon, iron and thorium.
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  • 21
    Publication Date: 2019-09-23
    Description: The deposition of atmospheric dust into the ocean has varied considerably over geological time1, 2. Because some of the trace metals contained in dust are essential plant nutrients which can limit phytoplankton growth in parts of the ocean, it has been suggested that variations in dust supply to the surface ocean might influence primary production3, 4. Whereas the role of trace metal availability in photosynthetic carbon fixation has received considerable attention, its effect on biogenic calcification is virtually unknown. The production of both particulate organic carbon and calcium carbonate (CaCO3) drives the ocean's biological carbon pump. The ratio of particulate organic carbon to CaCO3 export, the so-called rain ratio, is one of the factors determining CO2 sequestration in the deep ocean. Here we investigate the influence of the essential trace metals iron and zinc on the prominent CaCO3-producing microalga Emiliania huxleyi. We show that whereas at low iron concentrations growth and calcification are equally reduced, low zinc concentrations result in a de-coupling of the two processes. Despite the reduced growth rate of zinc-limited cells, CaCO3 production rates per cell remain unaffected, thus leading to highly calcified cells. These results suggest that changes in dust deposition can affect biogenic calcification in oceanic regions characterized by trace metal limitation, with possible consequences for CO2 partitioning between the atmosphere and the ocean.
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  • 22
    Publication Date: 2020-08-04
    Description: Aspects of the sea level changes in the western Mediterranean Sea are investigated using a numerical tidal model of the Strait of Gibraltar. As a prerequisite, the performance of this model, that is, a two-dimensional, nonlinear, two-layer, boundary-fitted coordinate numerical model based on the hydrostatic approximation on an f plane, is assessed in the simulation of mean and tidal circulation of the Strait of Gibraltar. The model is forced by imposing mean interface and surface displacements as well as M2, S2, O1, and K1 tidal components along the Atlantic and Mediterranean model open boundaries. Model results are compared with observations and with results obtained from a tidal inverse model for the eastern entrance of the Strait of Gibraltar. In general, good agreement is found. A sensitivity study performed by varying different model parameters shows that the model behaves reasonably well in the simulation of the averaged circulation. The model is then used to investigate the climatological sensitivity of the simulated dynamics in the Strait of Gibraltar to changes in the density difference between Atlantic and Mediterranean waters. For this purpose, given a certain density difference between Atlantic and Mediterranean waters, the authors iteratively searched for that sea level drop between the Atlantic and the Mediterranean that fulfills the mass balance of the Mediterranean. It is found that an increase of the density difference leads to an increase of the exchange flow and to an increase of the sea level drop between the two basins. A trend in the sea level drop of O(1 cm yr−1), such as the one observed between 1994 and 1997, is explained by the model as the result of a trend of O(10−4 yr−1) in the relative density difference between the Mediterranean and Atlantic waters. The observed north–south asymmetry in this trend is also captured by the model, and it is found to arise from changes in the along-strait velocity. Results suggest that the dynamics within the Strait of Gibraltar cannot be neglected when sea level changes in the western Mediterranean basin are investigated.
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  • 23
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 34 (12). pp. 2756-2760.
    Publication Date: 2020-08-04
    Description: The bifurcation behavior of a conceptual heat–salt oscillator model is analyzed by means of numerical continuation methods. A global (homoclinic) bifurcation acts as an organizing center for the dynamics of the simplified convective model. It originates from a codimension-2 bifurcation in an extended parameter space. Comparison with earlier work by Cessi shows that the intriguing stochastic thermohaline excitability can be understood from the bifurcation structure of the model. It is argued that global bifurcations may play a crucial role in determining long-term variability of the thermohaline circulation.
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  • 24
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    AMS (American Meteorological Society)
    In:  Journal of Climate, 17 . pp. 2157-2169.
    Publication Date: 2019-07-02
    Description: A method is presented to reconstruct decadal variations of the North Atlantic Oscillation (NAO). The spectral characteristics of the NAO on time scales of decades and longer are of particular interest for the understanding of North Atlantic ocean–atmosphere interactions. The reconstruction is based on a transfer model calibration that uses bandpass-filtered time series. The maximum overlap discrete wavelet transform (MODWT) is applied for decomposing the time series variance into different time scales. A total of 43 proxies, including Greenland ice cores and European tree-ring chronologies, are selected and regionally grouped providing four independent reconstructions for the period 1700–1978. The mean reconstruction agrees well with two recently published reconstructions during most of the time period. However, there are considerable differences in the earliest part before 1750. Running correlations between the reconstructions indicate that time-dependent relations exist among the different NAO reconstructions. The results suggest that the geographical distribution of proxies strongly affects the reconstruction and could explain some of the apparent discrepancies among the reconstructions recently published in literature. In the early eighteenth century, external forcing (solar, volcanic) seems to mask the NAO signature within the proxies
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  • 25
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 34 . pp. 1548-1570.
    Publication Date: 2020-08-04
    Description: The deep circulation and related transports of the southern Labrador Sea are determined from direct current observations from ship surveys and a moored current-meter array. The measurements covered a time span from summer 1997 to 1999 and show a well-defined deep boundary current extending approximately out to the 3300-m depth contour and weak reverse currents farther offshore. The flow has a strong barotropic component, and significant baroclinic flow is only found in the shallow Labrador Current at the shelf break and associated with a deep core of Denmark Strait Overflow Water. The total deep-water transport below σΘ = 27.74 kg m−3 was 26 ± 5 Sv (Sv ≡ 106 m3 s−1) comprising Labrador Sea Water (LSW), Gibbs Fracture Zone Water (GFZW), and Denmark Strait Overflow Water (DSOW). Intraseasonal variability of the flow and transport was high, ranging from 15 to 35 Sv, and the annual means differed by 17%. A seasonal cycle is confined to the shallow Labrador Current; in its deeper part, where the mean flow is still strong, no obvious seasonality could be detected. The transport of the interior anticyclonic recirculation was estimated from lowered acoustic Doppler current profiler stations and geostrophy, yielding about 9 Sv. Thus, the net deep-water outflow from the Labrador Sea was about 17 Sv. The baroclinic transport of GFZW and DSOW referenced to the depth of the isopycnal σΘ = 27.80 kg m−3 is only about one-third of the total transport in these layers. Longer-term variations of the total transports are not represented well by the baroclinic contribution.
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  • 26
    Publication Date: 2020-07-22
    Description: Microcionamides A (1) and B (2) have been isolated from the Philippine marine sponge Clathria (Thalysias) abietina. These new linear peptides are cyclized via a cystine moiety and have their C-terminus blocked by a 2-phenylethylenamine group. Their total structures, including absolute stereochemistry, were determined by a combination of spectral and chemical methods. Compound 1 was shown to slowly isomerize about the C-36/C-37 double bond when stored in DMSO. Microcionamides A (1) and B (2) exhibited significant cytotoxicity against the human breast tumor cells lines MCF-7 and SKBR-3 and displayed inhibitory activity against Mycobacterium tuberculosis H37Ra.
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  • 27
    Publication Date: 2020-09-03
    Description: Penicillium expansum is known for its destructive rot and patulin production in apple juice. According to the literature, P. expansum can, among other compounds, produce citrinin, ochratoxin A, patulin, penitrem A, and rubratoxin B. In this study the qualitative production of metabolites was examined using TLC (260 isolates), HPLC (85 isolates), and MS (22 isolates). The results showed that none of the 260 isolates produced ochratoxin A, penitrem A, or rubratoxin B. However, chaetoglobosin A and communesin B were produced consistently by all 260 isolates. Patulin and roquefortine C were produced by 98% of the isolates. Expansolides A/B and citrinin were detected in 91 and 85% of the isolates, respectively. Chaetoglobosins and communesins were detected in naturally infected juices and potato pulp, whereas neither patulin nor citrinin was found. Because most P. expansum isolates produce patulin, citrinin, chaetoglobosins, communesins, roquefortine C, and expansolides A and B, foods contaminated with this fungus should ideally be examined for chaetoglobosin A as well as patulin.
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  • 28
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    AMS (American Meteorological Society)
    In:  Journal of Climate, 17 (22). pp. 4463-4472.
    Publication Date: 2017-08-23
    Description: On seasonal time scales, ENSO prediction has become feasible in an operational framework in recent years. On decadal to multidecadal time scales, the variability of the oceanic circulation is assumed to provide a potential for climate prediction. To investigate the decadal predictability of the coupled atmosphere–ocean general circulation model (AOGCM) European Centre-Hamburg model version 5/Max Planck Institute Ocean Model (ECHAM5/MPI-OM), a 500-yr-long control integration and “perfect model” predictability experiments are analyzed. The results show that the sea surface temperatures (SSTs) of the North Atlantic, Nordic Seas, and Southern Ocean exhibit predictability on multidecadal time scales. Over the ocean, the predictability of surface air temperature (SAT) is very similar to that of SST. Over land, there is little evidence of decadal predictability of SAT except for some small maritime-influenced regions of Europe. The AOGCM produces predictable signals in lower-tropospheric temperature and precipitation over the North Atlantic, but not in sea level pressure.
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  • 29
    Publication Date: 2022-03-07
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  • 30
    Publication Date: 2022-03-10
    Description: The huge warming of the Arctic that started in the early 1920s and lasted for almost two decades is one of the most spectacular climate events of the twentieth century. During the peak period 1930–40, the annually averaged temperature anomaly for the area 60°–90°N amounted to some 1.7°C. Whether this event is an example of an internal climate mode or is externally forced, such as by enhanced solar effects, is presently under debate. This study suggests that natural variability is a likely cause, with reduced sea ice cover being crucial for the warming. A robust sea ice–air temperature relationship was demonstrated by a set of four simulations with the atmospheric ECHAM model forced with observed SST and sea ice concentrations. An analysis of the spatial characteristics of the observed early twentieth-century surface air temperature anomaly revealed that it was associated with similar sea ice variations. Further investigation of the variability of Arctic surface temperature and sea ice cover was performed by analyzing data from a coupled ocean–atmosphere model. By analyzing climate anomalies in the model that are similar to those that occurred in the early twentieth century, it was found that the simulated temperature increase in the Arctic was related to enhanced wind-driven oceanic inflow into the Barents Sea with an associated sea ice retreat. The magnitude of the inflow is linked to the strength of westerlies into the Barents Sea. This study proposes a mechanism sustaining the enhanced westerly winds by a cyclonic atmospheric circulation in the Barents Sea region created by a strong surface heat flux over the ice-free areas. Observational data suggest a similar series of events during the early twentieth-century Arctic warming, including increasing westerly winds between Spitsbergen and Norway, reduced sea ice, and enhanced cyclonic circulation over the Barents Sea. At the same time, the North Atlantic Oscillation was weakening.
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  • 31
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    Kluwer
    In:  Dordrecht, 396 pp., Kluwer, vol. 138, no. 2, pp. 527-553, (ISBN: 1-4020-1179-2)
    Publication Date: 2003
    Keywords: Earthquake risk ; Earthquake hazard ; interdisciplinary ; Textbook of geophysics ; Textbook of geology
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  • 32
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    Kluwer
    In:  Dordrecht, 552 pp., Kluwer, vol. 19, no. 22, pp. 662-664, (ISBN 1-4020-1244-6)
    Publication Date: 2003
    Keywords: Tsunami(s) ; Oceanography ; Earthquake hazard ; land ; slides ; submarine ; coast
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  • 33
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    Kluwer
    In:  Dordrecht, 348 pp., Kluwer, vol. 20, no. Publ. No. 12, pp. 81-89, (ISBN 1-4020-1729-4)
    Publication Date: 2003
    Keywords: GFZ ; M04.0014 ; 000266148 ; Textbook of geophysics ; Statistical investigations ; Artificial intelligence (AI) ; Seismics (controlled source seismology) ; Borehole geophys. ; Applied geophysics ; Electromagnetic methods/phenomena ; Seismology
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  • 34
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    Kluwer
    In:  Dordrecht, 388 pp., Kluwer, vol. 26, no. Publ. No. 12, pp. 95-104, (ISBN: 1-4020-1592-5)
    Publication Date: 2003
    Description: Data assimilation is the combination of information from observations and models of a particular physical system in order to get the best possible estimate of the state of that system. The technique has wide applications across a range of earth sciences, a major application being the production of operational weather forecasts. Others include oceanography, atmospheric chemistry, climate studies, and hydrology. Data Assimilation for the Earth System is a comprehensive survey of both the theory of data assimilation and its application in a range of earth system sciences. Data assimilation is a key technique in the analysis of remote sensing observations and is thus particularly useful for those analysing the wealth of measurements from recent research satellites. This book is suitable for postgraduate students and those working on the application of data assimilation in meteorology, oceanography and other earth sciences.
    Keywords: Modelling ; Data analysis / ~ processing ; Textbook of geophysics ; Textbook of geology ; TBMeteorology
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  • 35
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    Kluwer
    In:  Dordrecht, 368 pp., Kluwer, vol. 70, pp. 71-83, (ISBN: 1-4020-0821-X)
    Publication Date: 2003
    Description: Preface. 1. Introduction; B. Boots, et al. Part I: Statistical models of spatial systems. Section A: Spatial statistics. 2. Geographic patterns of urban residential development; J. Lee. 3. Using local statistics for boundary characterization; B. Boots. 4. Local spatial interaction modelling based on the geographically weighted regression approach; T. Nakaya. Section B: Space-time analysis. 5. Understanding activity scheduling and rescheduling behaviour: theory and numerical illustration; Chang-Hyeon Joh, et al. 6. Geographical model of a self-organizing megalopolis with time-space convergence; I. Mizuno. 7. Epidemic modelling of HIV/AIDS transfers between eastern and western Europe; P. Smith, R. Thomas. Part II: Computational methods. Section A: Simulation models. 8. A spatial microsimulation model for social policy evaluation; D. Ballas, et al. 9. Analysis of the effect of land use patterns on the anthropogenic energy discharged from air conditioning and hot water supply using a modified CSU mesoscale model; T. Watanabe, et al. 10. Generalized Thuenen and Thuenen-Ricardo models for Asian land use; K. Konagaya. Section B: GIS models. 11. Balancing consensus and conflict with a GIS-based multi-participant, multi-criteria decision support tool; R. D. Feick, G. B. Hall. 12. Grid-based population distribution estimates from historical Japanese topographical maps using GIS: Y. Arai, S. Koike. 13. GIS modelling for rain-induced debris-flow hazards in a small watershed; S. Zhao, T. Tamura. Section C: The internet. 14. A geographical interpretation of cyberspace: preliminary analysis on the scaling tendency of information spaces; N. Shiode. 15. On modelling internet transactions as a time-dependent random walk: an application of the retail aggregate space-time trip (RASTT) model; R. G. V. Baker. 16. Development of disaster information network system in the Asian region: internet GIS for disaster information management; Y. Ogawa, et al. 17. Geographical conceptualization of cyberplaces; M. Takeyama.
    Keywords: Modelling ; Data analysis / ~ processing ; Textbook of geophysics ; Textbook of geology ; TBMeteorology
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  • 36
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    Kluwer
    In:  Dordrecht, 616 pp., Kluwer, vol. 4, no. Subvol. b, pp. 220, (ISBN: 0-7923-5686-1)
    Publication Date: 2003
    Keywords: Textbook of geology ; geography ; GIS ; Global Positioning System ; pollution ; remote ; sensing ; Deep seismic sounding (espec. cont. crust) ; decision ; support ; system ; internet ; GSDI ; European ; CZM
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  • 37
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    Kluwer
    In:  Dordrecht, 356 pp., Kluwer, vol. 22, no. 1, pp. 799-804, (ISBN 1-4020-1777-4 (hb) and ISBN 1-4020-1778-2 (pb))
    Publication Date: 2003
    Keywords: Textbook of geophysics ; Seismology ; Seismicity ; Earthquake hazard ; Source ; Earthquake risk ; Earthquake engineering, engineering seismology ; Earthquake precursor: prediction research ; Greece ; Turkey
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  • 38
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    Kluwer
    In:  Dordrecht, 460 pp., Kluwer, vol. 17, pp. 225, (ISBN 1-4020-1408-2)
    Publication Date: 2003
    Description: Foreword. How to climb the gravity wall; R. Rummel. I: Precise orbit determination and gravity field modelling. Strategies for precise orbit determination of low earth orbiters using the Global Positioning System; U. Hugentobler, G. Beutler. Aiming at a 1 cm orbit for low earth orbiters: reduced-dynamic and kinematic precise orbit determination; P. N. A. M. Visser, J. van den Ijssel. Space-wise, time-wise, torus and Rosborough representations in gravity field modelling; N. Sneeuw. Gravity field recovery from GRACE: unique aspects of the high precision inter-satellite data and analysis methods; G. Balmino. Global gravity field recovery using solely Global Positioning System tracking and accelerometer data from CHAMP; C. Reigber, et al. The processing of band-limited measurements: filtering techniques in the least squares context and in the presence of data gaps; W.-D. Schuh. II: Solid earth physics. Long wavelength sea level and solis surface perturbations driven by polar ice mass variations: fingerprinting Greenland and Antarctic ice sheet flux; M. E. Tamisiea, et al. Benefits from GOCE within solid earth geophysics; A. M. Marotta. The potential of GOCE in constraining the structure of the crust and lithosphere from post-glacial rebound; L. L. A. Vermeersen. Deep and shallow solid-earth structures reconstructed with sequential integrated inversion (SII) of seismic and gravity data; R. Tondi, et al. Present-day sea level change: observations and causes; A. Cazenave, et al. III: Ocean circulation. Global ocean data assimilation and geoid measurements; C. Wunsch, D. Stammer. Resolution needed for an adequate determination of the mean ocean circulation from altimetry and an improved geoid; C. Le Provost, M. Bremond. Error characteristics estimated from CHAMP, GRACE and GOCE derived geoids and from satellite altimetry derived mean dynamic topography; E. J. O. Schrama. Estimating the high-resolution mean sea-surface velocity field by combined use of altimeter and drifter data for geoid model improvement; S. Imawaki, et al. Combined use of altimetry and in situ gravity data for coastal dynamics studies; K. Haines, et al. Feasibility and contribution to ocean circulation studies of ocean bottom pressure determination; C. W. Hughes, V. Stepanov. Impact of geoid improvement on ocean mass and heat transport estimates; P. Le Grand. How operational oceanography can benefit from dynamic topography estimates as derived from altimetry and improved geoid; P. Y. Le Traon, et al. IV: Geodesy. Remarks on the role of height datum in altimetry-gravity boundary-value problems; F. Sacerdote, F. Sanso. Ocean tides in GRACE monthly averaged gravity fields; P. Knudsen. Tidal models in a new era of satellite gravimetry; R. D. Ray, et al. The elusive stationary geoid; M. Vermeer. Geodetic methods for calibration of GRACE and GOCE; J. Bouman, R. Koop. V: Sea level. Benefits of GRACE and GOCE to sea level studies; P. Woodworth, J. M. Gregory. What might GRACE contribute to studies of post glacial rebound? J. Wahr, I. Velicogna. Measuring the distribution of ocean mass using GRACE; R. S. Nerem, et al. Monitoring changes in continental water storage with GRACE; S. Swenson, J. Wahr. VI: Future concepts. Attitude and drag control: an application to the GOCE satellite; E. Canuto, et al. On superconductive gravity gradiometry in space; S. Zarembinski. Satellite-satellite laser links for future gravity missions; P. L. Bender et al. Possible future use of laser gravity gradiometers; P. L. Bender, et al. MICROSCOPE instrument development lessons for GOCE; P. Touboul. Needs and tools for future gravity measuring missions; M. Aguirre-Martinez, N. Sneeuw. VII: Closing session. GOCE: first earth explorer core mission; M. R. Drinkwater, et al. Earth gravity field from space from senors to earth sciences: closing remarks; G. Beutler.
    Keywords: Textbook of geodesy ; Earth tides ; Least-squares ; Data analysis / ~ processing ; Geodesy ; Rheology ; Inelastic ; Crustal deformation (cf. Earthquake precursor: deformation or strain) ; Gravimetry, Gravitation ; Modelling
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  • 39
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    Kluwer
    In:  Dordrecht, 352 pp., Kluwer, vol. 4, no. 1, pp. 1-40, (ISBN: 1-4020-1348-5 hb, ISBN: 1-4020-1349-3 pb)
    Publication Date: 2003
    Keywords: Tsunami(s) ; Textbook of geophysics ; Textbook of geology ; Yalciner
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  • 40
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    Kluwer
    In:  Professional Paper, Geophysical Applications of Artificial Neural Networks and Fuzzy Logic, Dordrecht, Kluwer, vol. 4, no. 16, pp. 287-304, (ISBN 1-4020-1729-4)
    Publication Date: 2003
    Keywords: Statistical investigations ; Artificial intelligence (AI) ; Seismology ; Detectors ; Polarization ; NOISE ; Discrimination ; automatic ; picking
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  • 41
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    American Chemical Society
    In:  The Journal of Physical Chemistry A, 107 (7). pp. 1050-1054.
    Publication Date: 2020-05-11
    Description: We determined the coordination environment of Zn2+ in aqueous Cl- brines at 25 °C and 300 °C using ab initio molecular dynamics simulations. The ZnCl+ and ZnCl2 complexes exist as pseudo-octahedral ZnClm(H2O)6-m clusters at 25 °C but occur as pseudo-tetrahedral ZnClm(H2O)4-m clusters at 300 °C. The ZnCl3- complex occurs as the pseudo-tetrahedral ZnCl3(H2O)- cluster at 25 and 300 °C. The tetrahedral ZnCl42- complex, however, is the dominant Zn−Cl complex at 25 °C, at least in highly concentrated (7.4 m) Cl- brines. The change in hydration number with temperature for the ZnCl+ and ZnCl2 complexes will complicate extrapolations of solvation energies to hydrothermal conditions using a Born-model-based equation of state.
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  • 42
    Publication Date: 2016-09-07
    Description: Oceanic ecosystems altered by interdecadal climate variability may provide a feedback to the physical climate by phytoplankton affecting heat fluxes into the upper ocean and dimethylsulfide fluxes into the atmosphere
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  • 43
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    Nature Publishing Group
    In:  Nature, 421 (6922). pp. 520-523.
    Publication Date: 2016-05-10
    Description: Breaking waves markedly increase the rates of air–sea transfer of momentum, energy and mass. In light to moderate wind conditions, spilling breakers with short wavelengths are observed frequently. Theory and laboratory experiments have shown that, as these waves approach breaking in clean water, a ripple pattern that is dominated by surface tension forms at the crest. Under laboratory conditions and in theory, the transition to turbulent flow is triggered by flow separation under the ripples, typically without leading to overturning of the free surface15. Water surfaces in nature, however, are typically contaminated by surfactant films that alter the surface tension and produce surface elasticity and viscosity16, 17. Here we present the results of laboratory experiments in which spilling breaking waves were generated mechanically in water with a range of surfactant concentrations. We find significant changes in the breaking process owing to surfactants. At the highest concentration of surfactants, a small plunging jet issues from the front face of the wave at a point below the wave crest and entraps a pocket of air on impact with the front face of the wave. The bubbles and turbulence created during this process are likely to increase air–sea transfer.
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  • 44
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 33 . pp. 1990-1999.
    Publication Date: 2018-04-10
    Description: Intrinsic oscillations of stable geophysical surface frontal currents of the unsteady, nonlinear, reduced-gravity shallow-water equations on an f plane are investigated analytically and numerically. For frictional (Rayleigh) currents characterized by linear horizontal velocity components and parabolic cross sections, the primitive equations are reduced to a set of coupled nonlinear ordinary differential equations. In the inviscid case, two periodic analytical solutions of the nonlinear problem describing 1) the inertially reversing horizontal displacement of a surface frontal current having a fixed parabolic cross section and 2) the cross-front pulsation of a coastal current emerging from a motionless surface frontal layer are presented. In a linear and in a weakly nonlinear context, analytical expressions for field oscillations and their frequency shift relative to the inertial frequency are presented. For the fully nonlinear problem, solutions referring to a surface frontal coastal current are obtained analytically and numerically. These solutions show that the currents oscillate always superinertially, the frequency and the amplitude of their oscillations depending on the magnitude of the initial disturbance and on the squared current Rossby number. In a linear framework, it is shown that disturbances superimposed on the surface frontal current are standing waves within the bounded region, the frequencies of which are inertial/superinertial for the first mode/higher modes. In the same frame, a zeroth mode, which could be interpreted as the superposition of an inertial wave on a background vorticity field, would formally yield subinertial frequencies. For surface frontal currents affected by Rayleigh friction, it is shown that the magnitude of the mean current decays according to a power law and that the oscillations decay faster, because this decay follows an exponential law. Implications of the intrinsic oscillations and of their rapid dissipation for the near-inertial motion in an active ambient ocean are discussed.
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  • 45
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 33 . pp. 431-435.
    Publication Date: 2018-04-10
    Description: Aspects of the dynamics of warm-core eddies evolving in a deep ocean are investigated using the results of laboratory experiments and numerical simulations. The vortices, produced experimentally in a system brought to solid body rotation by rapidly lifting a bottomless cylinder containing freshwater immersed in a salty ambient fluid, show clearly the presence of inertial oscillations: deepenings and contractions, shoalings and expansions, alternate during an exact inertial period. These pulsations, though predicted analytically and simulated numerically, had never been measured before for surface eddies having aspect ratios, as well as Rossby and Burger numbers, typical of geophysical warm-core eddies. The spatial structure of the vortex radial and tangential velocity components is analyzed using the experimental results and numerical simulations carried out by means of a layered, nonlinear, reduced-gravity frontal model. It is found that, while the dependence of the vortex radial velocity on the vortex radius evolves toward linearity as time elapses, different spatial structures seem to be possible for the vortex tangential velocity dependence. This behavior, which strongly differs from the “pulson” dynamics, is instead consistent with recently found analytical solutions of the nonlinear, reduced-gravity shallow-water equations describing the dynamics of warm-core eddies on an f plane.
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  • 46
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 33 (1). pp. 75-87.
    Publication Date: 2018-04-11
    Description: Two large-scale free-drifting isobaric-floats experiments, “SOFARGOS”/Marine Science and Technology Programme, phase 2 (MAST2) and Mass Transfer and Ecosystem Response (MATER)/MAST3, undertaken in 1994–95 in the northwestern Mediterranean Sea and in 1997–98 in the Algerian Basin, respectively, have revealed for the first time that Western Mediterranean Deep Water, newly formed by deep convection in the Gulf of Lion (the so-called Medoc site), can be advected several hundreds of kilometers away from the formation area by anticyclonic submesoscale coherent vortices (SCVs). This behavior implies that SCVs participate actively in the large-scale thermohaline circulation and deep ventilation of the western Mediterranean Sea. These SCVs are characterized by small radius (5 km), very low potential vorticity, high aspect ratio (0.1), and extended lifetime (〉0.5 yr).
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  • 47
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 33 (7). pp. 1351-1364.
    Publication Date: 2019-04-29
    Description: Bulk properties of the Denmark Strait overflow (DSO) plume observed in velocity and hydrography surveys undertaken in 1997 and 1998 are described. Despite the presence of considerable short-term variability, it is found that the pathway and evolution of the plume density anomaly are remarkably steady. Bottom stress measurements show that the pathway of the plume core matches well with a rate of descent controlled by friction. The estimated entrainment rate diagnosed from the rate of plume dilution with distance shows a marked increase in entrainment at approximately 125 km from the sill, leading to a net dilution consistent with previous reports of a doubling of overflow transport measured by current meter arrays. The entrainment rate increase is likely related to the increased topographic slopes in the region, compounded by a decrease in interface stratification as the plume is diluted and enters a denser background.
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  • 48
    Publication Date: 2015-11-24
    Description: Noble-gas geochemistry is an important tool for understanding planetary processes from accretion to mantle dynamics and atmospheric formation. Central to much of the modelling of such processes is the crystal–melt partitioning of noble gases during mantle melting, magma ascent and near-surface degassing5. Geochemists have traditionally considered the 'inert' noble gases to be extremely incompatible elements, with almost 100 per cent extraction efficiency from the solid phase during melting processes. Previously published experimental data on partitioning between crystalline silicates and melts has, however, suggested that noble gases approach compatible behaviour, and a significant proportion should therefore remain in the mantle during melt extraction. Here we present experimental data to show that noble gases are more incompatible than previously demonstrated, but not necessarily to the extent assumed or required by geochemical models. Independent atomistic computer simulations indicate that noble gases can be considered as species of 'zero charge' incorporated at crystal lattice sites. Together with the lattice strain model9, 10, this provides a theoretical framework with which to model noble-gas geochemistry as a function of residual mantle mineralogy.
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  • 49
    Publication Date: 2015-01-26
    Description: The results of the first protozoological study in terms of paleoecology of long-term sediments and buried soils formed in the cryolite zone of northeastern Siberia are discussed. The data on testaceans (Protozoa: Testacea) inhabiting various sites of Bykovsky Peninsula, Laptev Sea coast near estuary of Lena, within the last 53 000 years (Late Pleistocene and Holocene) are presented.
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  • 50
    Publication Date: 2017-05-30
    Description: High-performance liquid chromatography-electrospray ionization mass spectrometry was applied to the detection of the iron(III) complexes of the hydroxamate siderophores rhodotoluric acid, deferrioxamine B, and deferrichrome. Separation of the iron(III) complexes was obtained using a polystyrene-divinylbenzene stationary phase. The retention and responses of ferrioxamine and ferrichrome were optimal when a gradient elution program with methanol and 0.1% (v/v) formic acid as the mobile phases was used. These conditions were also suitable for the retention and separation of the uncomplexed ligands. Retention of iron(III) rhodotoluate was improved when formic acid was replaced by the ion-pairing reagent heptafluorobutyric acid (0.1%). Detection limits for the ferric complexes, defined as 3 SD of the lowest determined standard, were 26 nM for iron(III) rhodotoluate, 0.23 nM for ferrioxamine, and 0.40 nM for ferrichrome. A protocol for the solid-phase extraction of these hydroxamate siderophores from seawater was developed and applied to the extraction of siderophores from enriched incubated seawater samples.
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  • 51
    Publication Date: 2017-05-30
    Description: High-performance liquid chromatography-electrospray ionization mass spectrometry was applied to the detection of the iron(III) complexes of the hydroxamate siderophores rhodotoluric acid, deferrioxamine B, and deferrichrome. Separation of the iron(III) complexes was obtained using a polystyrene-divinylbenzene stationary phase. The retention and responses of ferrioxamine and ferrichrome were optimal when a gradient elution program with methanol and 0.1% (v/v) formic acid as the mobile phases was used. These conditions were also suitable for the retention and separation of the uncomplexed ligands. Retention of iron(III) rhodotoluate was improved when formic acid was replaced by the ion-pairing reagent heptafluorobutyric acid (0.1%). Detection limits for the ferric complexes, defined as 3 SD of the lowest determined standard, were 26 nM for iron(III) rhodotoluate, 0.23 nM for ferrioxamine, and 0.40 nM for ferrichrome. A protocol for the solid-phase extraction of these hydroxamate siderophores from seawater was developed and applied to the extraction of siderophores from enriched incubated seawater samples.
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  • 52
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    AMS (American Meteorological Society)
    In:  Journal of Atmospheric and Oceanic Technology, 20 (5). pp. 742-751.
    Publication Date: 2020-08-04
    Description: A new shipboard current profiler, a 75-kHz ocean surveyor, was operationally used during two research cruises in the tropical Atlantic and the subpolar North Atlantic, respectively. Here, a report is presented on the first experience with this instrument in two very different current regimes, in the Tropics with large vertical shears, and in the subpolar regime with mainly barotropic flow. The ocean surveyor continuously measured currents in the upper ocean from near the surface to about 500–700-m depth. The measurement range showed a dependence on the regional and temporal variations of scattering particles and on the intensity of swell and wind waves. Statistical comparisons are performed with on-station lowered acoustic Doppler current profiler (LADCP) profiles and underway measurements by classic shipboard acoustic Doppler current profiler (ADCP) measurements. Accuracy estimates for hourly averaged ocean surveyor currents result in errors of about 1 cm s–1 for on-station data and of 2–4 cm s–1 for underway measurements, depending on the regional abundance of scatterers and on the weather conditions encountered.
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  • 53
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    AMS (American Meteorological Society)
    In:  Journal of the Atmospheric Sciences, 60 . pp. 152-165.
    Publication Date: 2018-04-16
    Description: A new mechanism is proposed that explains two key features of the observed El Niño–Southern Oscillation (ENSO) phenomenon—its irregularity and decadal amplitude changes. Using a low-order ENSO model, the authors show that the nonlinearities in the tropical heat budget can lead to bursting behavior characterized by decadal occurrences of strong El Niño events. La Niña events are not affected, a feature that is also seen in ENSO observations. One key result of this analysis is that decadal variability in the Tropics can be generated without invoking extratropical processes or stochastic forcing. The El Niño bursting behavior simulated by the low-order ENSO model can be understood in terms of the concept of homoclinic and heteroclinic connections. It is shown that this new model for ENSO amplitude modulations and irregularity, although difficult to prove, might explain some features of ENSO dynamics seen in more complex climate models and the observations.
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  • 54
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    In:  Journal of Physical Oceanography, 33 . pp. 2307-2319.
    Publication Date: 2018-04-10
    Description: Processes that influence the volume and heat transport across the Greenland–Scotland Ridge system are investigated in a numerical model with ° horizontal resolution. The focus is on the sensitivity of cross-ridge transports and the reaction of the subpolar North Atlantic Ocean circulation to changes in wind stress and buoyancy forcing on seasonal to interannual timescales. A general relation between changes in wind stress or cross-ridge density contrasts and the overturning transport of Greenland–Iceland–Norwegian Seas source water is established from a series of idealized experiments. The relation is used subsequently to interpret changes in an experiment over the years 1992–97 with realistic forcing. On seasonal and interannual timescales there is a clear correlation between heat flux and wind stress curl variability. The realistic model suggests a steady decrease in the strength of the cyclonic subpolar gyre of the North Atlantic with a corresponding decrease in heat transport during the 1990s
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  • 55
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    AMS (American Meteorological Society)
    In:  Journal of Climate, 16 (15). pp. 2569-2585.
    Publication Date: 2020-08-04
    Description: The role of mean and stochastic freshwater forcing on the generation of millennial-scale climate variability in the North Atlantic is studied using a low-order coupled atmosphere–ocean–sea ice model. It is shown that millennial-scale oscillations can be excited stochastically, when the North Atlantic Ocean is fresh enough. This finding is used in order to interpret the aftermath of massive iceberg surges (Heinrich events) in the glacial North Atlantic, which are characterized by an excitation of Dansgaard–Oeschger events. Based on model results, it is hypothesized that Heinrich events trigger Dansgaard–Oeschger cycles and that furthermore the occurrence of Heinrich events is dependent on the accumulated climatic effect of a series of Dansgaard–Oeschger events. This scenario leads to a coupled ocean–ice sheet oscillation that shares many similarities with the Bond cycle. Further sensitivity experiments reveal that the timescale of the oscillations can be decomposed into stochastic, linear, and nonlinear deterministic components. A schematic bifurcation diagram is used to compare theoretical results with paleoclimatic data.
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  • 56
    Publication Date: 2017-03-07
    Description: More than 50% of the Earth' s surface is sea floor below 3,000 m of water. Most of this major reservoir in the global carbon cycle and final repository for anthropogenic wastes is characterized by severe food limitation. Phytodetritus is the major food source for abyssal benthic communities, and a large fraction of the annual food load can arrive in pulses within a few days1, 2. Owing to logistical constraints, the available data concerning the fate of such a pulse are scattered3, 4 and often contradictory5, 6, 7, 8, 9, 10, hampering global carbon modelling and anthropogenic impact assessments. We quantified (over a period of 2.5 to 23 days) the response of an abyssal benthic community to a phytodetritus pulse, on the basis of 11 in situ experiments. Here we report that, in contrast to previous hypotheses5, 6, 7, 8, 9, 10, 11, the sediment community oxygen consumption doubled immediately, and that macrofauna were very important for initial carbon degradation. The retarded response of bacteria and Foraminifera, the restriction of microbial carbon degradation to the sediment surface, and the low total carbon turnover distinguish abyssal from continental-slope ‘deep-sea’ sediments.
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  • 57
    Publication Date: 2017-03-07
    Description: The shells of the planktonic foraminifer Neogloboquadrina pachyderma have become a classical tool for reconstructing glacial–interglacial climate conditions in the North Atlantic Ocean1, 2, 3. Palaeoceanographers utilize its left- and right-coiling variants, which exhibit a distinctive reciprocal temperature and water mass related shift in faunal abundance both at present and in late Quaternary sediments1, 2, 4, 5. Recently discovered cryptic genetic diversity in planktonic foraminifers6, 7, 8 now poses significant questions for these studies. Here we report genetic evidence demonstrating that the apparent ‘single species’ shell-based records of right-coiling N. pachyderma used in palaeoceanographic reconstructions contain an alternation in species as environmental factors change. This is reflected in a species-dependent incremental shift in right-coiling N. pachyderma shell calcite δ18O between the Last Glacial Maximum and full Holocene conditions. Guided by the percentage dextral coiling ratio, our findings enhance the use of δ18O records of right-coiling N. pachyderma for future study. They also highlight the need to genetically investigate other important morphospecies to refine their accuracy and reliability as palaeoceanographic proxies.
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  • 58
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    In:  Journal of Climate, 16 . pp. 2717-2734.
    Publication Date: 2018-07-24
    Description: Synoptic-scale variability in the air–sea turbulent fluxes in the areas of midlatitudinal western boundary currents is analyzed. In the Gulf Stream area, ocean–atmosphere fluxes on synoptic time- and space scales are clearly coordinated with the propagating synoptic-scale atmospheric transients. The statistical analysis of 6-hourly resolution sea level pressure and surface turbulent fluxes from the NCEP–NCAR reanalysis for the period from 1948 to 2000 in the area of strong sea surface temperature gradients in the Gulf Stream gives strong proof for the association between the propagating cyclones and synoptic patterns of surface turbulent fluxes. It is shown that sea–air interaction in this area is controlled by the sharpness of surface temperature gradients in the ocean and by the intensity of the advection of the air masses in different parts of cyclones during the cold-air and warm-air outbreaks. A simple parameter based on the joint consideration of the characteristics of sea surface temperature and sea level pressure fields is used to characterize the synoptic variability of air–sea turbulent fluxes. The effectiveness of the relationship between surface temperature and surface pressure on one side and air–sea flux anomalies on the other vary from year to year in phase with variability in the frequencies of deep atmospheric cyclones in the Gulf Stream area. The limits of applicability of the approach, its sensitivity to higher-resolution sea surface temperature data, and the possibility of its further applications are discussed.
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  • 59
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    Nature Publishing Group
    In:  Nature, 422 . pp. 602-606.
    Publication Date: 2019-09-23
    Description: The Messinian salinity crisis—the desiccation of the Mediterranean Sea between 5.96 and 5.33 million years (Myr) ago1—was one of the most dramatic events on Earth during the Cenozoic era2. It resulted from the closure of marine gateways between the Atlantic Ocean and the Mediterranean Sea, the causes of which remain enigmatic. Here we use the age and composition of volcanic rocks to reconstruct the geodynamic evolution of the westernmost Mediterranean from the Middle Miocene epoch to the Pleistocene epoch (about 12.1–0.65 Myr ago). Our data show that a marked shift in the geochemistry of mantle-derived volcanic rocks, reflecting a change from subduction-related to intraplate-type volcanism, occurred between 6.3 and 4.8 Myr ago, largely synchronous with the Messinian salinity crisis. Using a thermomechanical model, we show that westward roll back of subducted Tethys oceanic lithosphere and associated asthenospheric upwelling provides a plausible mechanism for producing the shift in magma chemistry and the necessary uplift (approx1 km) along the African and Iberian continental margins to close the Miocene marine gateways, thereby causing the Messinian salinity crisis.
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  • 60
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    In:  Journal of Radionanalytical and Nuclear Chemistry, 256 (3). pp. 473-480.
    Publication Date: 2019-09-23
    Description: A new method is presented for rapid and selective enrichment of radium in natural samples using 225Ra as a chemical yield tracer. The new technique allows a complete separation of the target nuclide from the sample matrix with high separation factors for thorium and uranium. The use of EmporeÔ Radium Rad Disks combines the easy handling of column chromatography with the high selectivity and rapid extraction kinetics of solvent extraction chromatography. Following this new chemical approach, eluates are obtained which are well suited for a-spectrometric analysis of Ra, Th and U.
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  • 61
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    Nature Publishing Group
    In:  Nature, 421 (6921). pp. 324-325.
    Publication Date: 2016-07-19
    Description: An excellent sediment record from the Arabian Sea traces recent patterns in the activity of the Asian monsoon. It reveals both variability in monsoon strength and links with climatic events elsewhere. The monsoon is the main determinant of environmental conditions over much of Asia, and so affects the most densely populated region on Earth. Differential heating of the north Indian Ocean and the northwest Pacific, and of the Asian land-mass, cause the seasonal reversal of monsoon winds. In summer, these winds blow northwards over the northern Indian Ocean, carrying huge amounts of moisture over the neighbouring land. The ensuing heavy rainfall can have devastating consequences for human life and livelihood. Conversely, agriculture in Asia depends on monsoon rains; and the seasonal upwelling of nutrient-laden subsurface waters, driven by monsoon winds, is essential to the success of coastal fisheries.
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  • 62
    Publication Date: 2016-07-19
    Description: A high-resolution mapping and sampling study of the Gakkel ridge was accomplished during an international ice-breaker expedition to the high Arctic and North Pole in summer 2001. For this slowest-spreading endmember of the global mid-ocean-ridge system, predictions were that magmatism should progressively diminish as the spreading rate decreases along the ridge, and that hydrothermal activity should be rare. Instead, it was found that magmatic variations are irregular, and that hydrothermal activity is abundant. A 300-kilometre-long central amagmatic zone, where mantle peridotites are emplaced directly in the ridge axis, lies between abundant, continuous volcanism in the west, and large, widely spaced volcanic centres in the east. These observations demonstrate that the extent of mantle melting is not a simple function of spreading rate: mantle temperatures at depth or mantle chemistry (or both) must vary significantly along-axis. Highly punctuated volcanism in the absence of ridge offsets suggests that first-order ridge segmentation is controlled by mantle processes of melting and melt segregation. The strong focusing of magmatic activity coupled with faulting may account for the unexpectedly high levels of hydrothermal activity observed.
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  • 63
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    In:  Journal of Climate, 16 (20). pp. 3371-3382.
    Publication Date: 2017-07-20
    Description: Recent observational studies have shown that the centers of action of interannual variability of the North Atlantic Oscillation (NAO) were located farther eastward during winters of the period 1978–97 compared to previous decades of the twentieth century. In this study, which focuses on the winter season (December–March), new diagnostics characterizing this shift are presented. Further, the importance of this shift for NAO-related interannual climate variability in the North Atlantic region is discussed. It is shown that an NAO-related eastward shift in variability can be found for a wide range of different parameters like the number of deep cyclones, near-surface air temperature, and turbulent surface heat flux throughout the North Atlantic region. By using a near-surface air temperature dataset that is homogenous with respect to the kind of observations used, it is shown that the eastward shift is not an artifact of changes in observational practices that took place around the late 1970s. Finally, an EOF-based Monte Carlo test is developed to quantify the probability of changes in the spatial structure of interannual NAO variability for a relatively short (20 yr) time series given multivariate “white noise.” It is estimated that the likelihood for differences in the spatial structure of the NAO between two independent 20-yr periods, which are similar (as measured by the angle and pattern correlation between two NAO patterns) to the observed differences, to occur just by chance is about 18%. From the above results it is argued that care has to be taken when conclusions about long-term properties of NAO-related climate variability are being drawn from relatively short recent observational data (e.g., 1978–97).
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  • 64
    Publication Date: 2019-02-26
    Description: A 20-Myr record of creation of oceanic lithosphere is exposed along a segment of the central Mid-Atlantic Ridge on an uplifted sliver of lithosphere. The degree of melting of the mantle that is upwelling below the ridge, estimated from the chemistry of the exposed mantle rocks, as well as crustal thickness inferred from gravity measurements, show oscillations of ∼3–4 Myr superimposed on a longer-term steady increase with time. The time lag between oscillations of mantle melting and crustal thickness indicates that the mantle is upwelling at an average rate of ∼25 mm yr-1, but this appears to vary through time. Slow-spreading lithosphere seems to form through dynamic pulses of mantle upwelling and melting, leading not only to along-axis segmentation but also to across-axis structural variability. Also, the central Mid-Atlantic Ridge appears to have become steadily hotter over the past 20 Myr, possibly owing to north–south mantle flow.
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  • 65
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    Nature Publishing Group
    In:  Nature, 426 (6965). p. 401.
    Publication Date: 2017-03-07
    Description: The speed at which mid-ocean ridges grind out new ocean floor varies considerably. The slowest-spreading ridges are especially tough to study — but the latest data show that they are especially intriguing.
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  • 66
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    AMS (American Meteorological Society)
    In:  Journal of Climate, 16 . pp. 1094-1098.
    Publication Date: 2018-07-24
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  • 67
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 33 (12). pp. 2719-2737.
    Publication Date: 2018-04-10
    Description: A new type of ocean general circulation model with simplified physics is described and tested for various simple wind-driven circulation problems. The model consists of the vorticity balance of the depth-averaged flow and a hierarchy of equations for “vertical moments” of density and baroclinic velocity. The first vertical density moment is the (vertically integrated) potential energy, which is used to describe the predominant link between the barotropic and the baroclinic oceanic flow in the presence of sloping topography. Tendency equations for the vertical moments of density and baroclinic velocity and an appropriate truncation of the coupled hierarchy of moments are derived that, together with the barotropic vorticity balance, yield a closed set of equations describing the barotropic–baroclinic interaction (BARBI) model of the oceanic circulation. Idealized companion experiments with a numerical implementation of the BARBI model and a primitive equation model indicate that wave propagation properties and baroclinic adjustments are correctly represented in BARBI in midlatitudes as well as in equatorial latitudes. Furthermore, a set of experiments with a realistic application to the Atlantic/Southern Ocean system reproduces important aspects that have been previously reported by studies of gyre circulations and circumpolar currents using full primitive equation models
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  • 68
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    Nature Publishing Group
    In:  Nature (423). pp. 280-283.
    Publication Date: 2017-03-07
    Description: Serious concerns have been raised about the ecological effects of industrialized fishing1, 2, 3, spurring a United Nations resolution on restoring fisheries and marine ecosystems to healthy levels4. However, a prerequisite for restoration is a general understanding of the composition and abundance of unexploited fish communities, relative to contemporary ones. We constructed trajectories of community biomass and composition of large predatory fishes in four continental shelf and nine oceanic systems, using all available data from the beginning of exploitation. Industrialized fisheries typically reduced community biomass by 80% within 15 years of exploitation. Compensatory increases in fast-growing species were observed, but often reversed within a decade. Using a meta-analytic approach, we estimate that large predatory fish biomass today is only about 10% of pre-industrial levels. We conclude that declines of large predators in coastal regions5 have extended throughout the global ocean, with potentially serious consequences for ecosystems5, 6, 7. Our analysis suggests that management based on recent data alone may be misleading, and provides minimum estimates for unexploited communities, which could serve as the 'missing baseline'8 needed for future restoration efforts.
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  • 69
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    AMS (American Meteorological Society)
    In:  Journal of Climate, - (16). pp. 443-460.
    Publication Date: 2020-08-04
    Description: A simple stochastic atmosphere model is coupled to a realistic model of the North Atlantic Ocean. A north–south SST dipole, with its zero line centered along the subpolar front, influences the atmosphere model, which in turn forces the ocean model by surface fluxes related to the North Atlantic Oscillation. The coupled system exhibits a damped decadal oscillation associated with the adjustment through the ocean model to the changing surface forcing. The oscillation consists of a fast wind-driven, positive feedback of the ocean and a delayed negative feedback orchestrated by overturning circulation anomalies. The positive feedback turns out to be necessary to distinguish the coupled oscillation from that in a model without any influence from the ocean to the atmosphere. Using a novel diagnosing technique, it is possible to rule out the importance of baroclinic wave processes for determining the period of the oscillation, and to show the important role played by anomalous geostrophic advection in sustaining the oscillation.
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  • 70
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    Kluwer
    In:  Fossil and recent biofilms. A natural history of life on Earth
    Publication Date: 2022-03-21
    Type: info:eu-repo/semantics/bookPart
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  • 71
    Publication Date: 2023-09-26
    Description: The dehydration of subducting oceanic crust and upper mantle has been inferred both to promote the partial melting leading to arc magmatism and to induce intraslab intermediate-depth earthquakes, at depths of 50–300 km. Yet there is still no consensus about how slab hydration occurs or where and how much chemically bound water is stored within the crust and mantle of the incoming plate. Here we document that bending-related faulting of the incoming plate at the Middle America trench creates a pervasive tectonic fabric that cuts across the crust, penetrating deep into the mantle. Faulting is active across the entire ocean trench slope, promoting hydration of the cold crust and upper mantle surrounding these deep active faults. The along-strike length and depth of penetration of these faults are also similar to the dimensions of the rupture area of intermediate-depth earthquakes.
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  • 72
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    In:  Professional Paper, Integration of Earth Science Research on the Turkish and Greek 1999 Earthquakes, Dordrecht, Kluwer, vol. 65, no. 16, pp. 61-70, (ISBN 1-86239-165-3, vi + 330 pp.)
    Publication Date: 2002
    Keywords: Sea seismics ; Fault zone ; NAF ; Deep seismic sounding (espec. cont. crust) ; Tectonics ; Cagatay ; Goeruer ; Gorur ; Turkey
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  • 73
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    Kluwer
    In:  Professional Paper, Integration of Earth Science Research on the Turkish and Greek 1999 Earthquakes, Dordrecht, Kluwer, vol. 48, no. 231, pp. 101-111, (ISBN: 3-540-23712-7)
    Publication Date: 2002
    Keywords: Seismicity ; historical ; Earthquake hazard ; Goeruer ; Gorur ; Turkey
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  • 74
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    Kluwer
    In:  Professional Paper, Integration of Earth Science Research on the Turkish and Greek 1999 Earthquakes, Dordrecht, Kluwer, vol. 24, no. 231, pp. 197-204, (ISBN: 3-540-23712-7)
    Publication Date: 2002
    Keywords: Modelling ; Crustal deformation (cf. Earthquake precursor: deformation or strain) ; Digital elevation model ; InSAR ; optical ; aerial ; photographs ; remote ; sensing ; Goeruer ; Gorur ; Greece
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  • 75
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    Kluwer
    In:  Bull., Polar Proj. OP-O3A4, Integration of Earth Science Research on the Turkish and Greek 1999 Earthquakes, Dordrecht, Kluwer, vol. 20, no. 4, pp. 113-128, (ISBN 0080419208)
    Publication Date: 2002
    Keywords: Earthquake ; Tectonics ; Geol. aspects ; Site amplification ; rockfall ; landslide ; cracks and fractures (.NE. fracturing) ; Crustal deformation (cf. Earthquake precursor: deformation or strain) ; Goeruer ; Gorur ; Greece
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  • 76
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    Kluwer
    In:  Bull., Open-File Rept., Integration of Earth Science Research on the Turkish and Greek 1999 Earthquakes, Dordrecht, Kluwer, vol. 54, no. 1, pp. 141-152, (ISBN 0080419208)
    Publication Date: 2002
    Keywords: Stress ; Earthquake precursor: prediction research ; Turkey ; Izmit ; Goeruer ; Gorur
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  • 77
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    Kluwer
    In:  Dordrecht, 772 pp., Kluwer, vol. 13, no. 3, pp. 632 pp., (ISBN 052)
    Publication Date: 2002
    Keywords: Textbook of mathematics ; Pattern recognition ; Statistical investigations ; computer ; science ; electrical ; engineering
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  • 78
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    In:  Dordrecht, Kluwer, vol. 10, no. Subvol. b, pp. 220, (ISBN 1-4020-0653-5)
    Publication Date: 2002
    Keywords: Textbook of geophysics ; Earthquake ; Seismology ; Tectonics ; Plate tectonics ; Strong motions ; Sea seismics ; Geol. aspects ; Tsunami(s) ; Earthquake catalog ; Seismicity ; Velocity depth profile ; Stress ; triggering ; Earthquake hazard ; Crustal deformation (cf. Earthquake precursor: deformation or strain) ; Geodesy ; Turkey ; Greece ; Goeruer ; Gorur
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  • 79
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    In:  Professional Paper, Integration of Earth Science Research on the Turkish and Greek 1999 Earthquakes, Dordrecht, Kluwer, vol. 23, no. Subvol. b, pp. 1-15, (ISBN: 3-540-23712-7)
    Publication Date: 2002
    Keywords: Crustal deformation (cf. Earthquake precursor: deformation or strain) ; surface ; rupture ; Source parameters ; Inversion ; seismic Moment ; release ; Seismology ; NAF ; Earthquake ; Oezaksoy ; Ozaksoy ; Goelcuek ; Golcuk ; Duezce ; Duzce ; Goekten ; Gokten ; Goeruer ; Gorur ; Adapazari ; Cemen ; Pinar
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  • 80
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    Kluwer
    In:  Integration of Earth Science Research on the Turkish and Greek 1999 Earthquakes, Dordrecht, Kluwer, vol. 65, pp. 35-46
    Publication Date: 2002
    Keywords: Geol. aspects ; Plate tectonics ; Tectonics ; Fault zone ; NAF ; Goeruer ; Gorur ; Turkey ; Yaltirak
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  • 81
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    In:  Professional Paper, Integration of Earth Science Research on the Turkish and Greek 1999 Earthquakes, Dordrecht, Kluwer, vol. 65, no. 16, pp. 175-196, (ISBN 1-86239-165-3, vi + 330 pp.)
    Publication Date: 2002
    Keywords: Seismicity ; Earthquake hazard ; Turkey ; Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Goeruer ; Gorur ; Greece
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  • 82
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    In:  Professional Paper, Integration of Earth Science Research on the Turkish and Greek 1999 Earthquakes, Dordrecht, Kluwer, vol. 65, no. 16, pp. 127-139, (ISBN 1-4020-1729-4)
    Publication Date: 2002
    Keywords: Velocity depth profile ; Three dimensional ; Seismicity ; Greece ; P-waves ; Tomography ; Goeruer ; Gorur
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  • 83
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    Kluwer
    In:  Dordrecht, 358 pp., Kluwer, vol. 10, no. Subvol. b, pp. 220, (ISBN 1-4020-0653-5)
    Publication Date: 2002
    Keywords: Textbook of geophysics ; Seismics (controlled source seismology) ; Seismology ; Layers ; Velocity depth profile ; Physical properties of rocks
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  • 84
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    In:  Professional Paper, Integration of Earth Science Research on the Turkish and Greek 1999 Earthquakes, Dordrecht, Kluwer, vol. 6, no. 16, pp. 17-34, (ISBN 0080419208)
    Publication Date: 2002
    Keywords: Strong motions ; Seismology ; seismic Moment ; Source ; Peak ground velocity ; Modelling ; Synthetic seismograms ; Goeruer ; Gorur ; Turkey ; Toksoez ; Toksoz ; NAF ; Earthquake
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  • 85
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    In:  Bull., Polar Proj. OP-O3A4, Integration of Earth Science Research on the Turkish and Greek 1999 Earthquakes, Dordrecht, Kluwer, vol. 46, no. XVI:, pp. 61-85, (ISBN: 3-540-23712-7)
    Publication Date: 2002
    Keywords: Geochemistry ; Tectonics ; Fault zone ; NAF ; Hydraulic fracturingSWEEP ; PARASOUND ; samples ; Kuscu ; Pekdeger ; Goeruer ; Gorur ; Turkey
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  • 86
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    In:  Bull., Open-File Rept., Integration of Earth Science Research on the Turkish and Greek 1999 Earthquakes, Dordrecht, Kluwer, vol. 54, no. 1, pp. 153-173, (ISBN 0080419208)
    Publication Date: 2002
    Keywords: Earthquake hazard ; historical ; Seismicity ; Geol. aspects ; Tectonics ; Crustal deformation (cf. Earthquake precursor: deformation or strain) ; Review article ; Goeruer ; Gorur
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  • 87
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    In:  Professional Paper, Open-File Rept., Integration of Earth Science Research on the Turkish and Greek 1999 Earthquakes, Dordrecht, Kluwer, vol. 9, no. 16, pp. 47-59, (ISBN 0080419208)
    Publication Date: 2002
    Keywords: Sea seismics ; Fault zone ; NAF ; Deep seismic sounding (espec. cont. crust) ; Tectonics ; Ulug ; Goeruer ; Gorur ; Turkey ; Oezel ; Ozel
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  • 88
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    In:  Bull., Open-File Rept., Integration of Earth Science Research on the Turkish and Greek 1999 Earthquakes, Dordrecht, Kluwer, vol. 1, no. 1, pp. 87-100, (ISBN 1-86239-165-3, vi + 330 pp.)
    Publication Date: 2002
    Keywords: Tsunami(s) ; Seismicity ; Earthquake hazard ; Goeruer ; Gorur
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  • 89
    Publication Date: 2017-07-07
    Description: According to small subunit ribosomal RNA (ss rRNA) sequence comparisons all known Archaea belong to the phyla Crenarchaeota, Euryarchaeota, and—indicated only by environmental DNA sequences—to the 'Korarchaeota'1, 2. Here we report the cultivation of a new nanosized hyperthermophilic archaeon from a submarine hot vent. This archaeon cannot be attached to one of these groups and therefore must represent an unknown phylum which we name 'Nanoarchaeota' and species, which we name 'Nanoarchaeum equitans'. Cells of 'N. equitans' are spherical, and only about 400 nm in diameter. They grow attached to the surface of a specific archaeal host, a new member of the genus Ignicoccus3. The distribution of the 'Nanoarchaeota' is so far unknown. Owing to their unusual ss rRNA sequence, members remained undetectable by commonly used ecological studies based on the polymerase chain reaction4. 'N. equitans' harbours the smallest archaeal genome; it is only 0.5 megabases in size. This organism will provide insight into the evolution of thermophily, of tiny genomes and of interspecies communication.
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  • 90
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    Kluwer
    In:  In: Marine Issues. Kluwer, Den Haag, pp. 203-220.
    Publication Date: 2018-02-23
    Type: Book chapter , NonPeerReviewed
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  • 91
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    Kluwer
    In:  Non-State Actors and International Law, 2 . pp. 279-300.
    Publication Date: 2020-06-22
    Description: Marine biological resources in general and biological resources of the deep sea and the deep seabed in particular are threatened by a variety of human activities. Those activities considered marine scientific research and related activities such as scientific sampling and bioprospecting can pose a threat to the conservation of these biological resources if performed in an unrestricted manner. Whether legal rules on marine scientific research should be applicable to highly commercial activities such as bioprospecting is doubtful. The current legal regulations provided by the UN Convention on the Law of the Sea and the Convention on Biological Diversity are not designed to provide for an adequate regime on the protection of biological resources in areas located outside national sovereignty. As a result, a new treaty on the protection and sustainable use of marine biological resources located outside national jurisdiction is necessary and must focus upon a common heritage approach. An institutional framework for such a regime can either be newly established together with an agreement or be established by an existing institution e.g. the International Seabed Authority.
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  • 92
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    AMS (American Meteorological Society)
    In:  Journal of the Atmospheric Sciences, 59 . pp. 2951-2965.
    Publication Date: 2018-04-16
    Description: This study investigates and accounts for the influence of various ice cloud parameters on the retrieval of the surface solar radiation budget (SSRB) from reflected flux at the top of the atmosphere (TOA). The optical properties of ice clouds depend on ice crystal shape, size distribution, water content, and the vertical profiles of geometric and microphysical structure. As a result, the relationship between the SSRB and TOA-reflected flux for an ice cloud atmosphere is more complex and differs from that for water cloud and cloudless atmospheres. The sensitivities of the relationship between the SSRB and TOA-reflected flux are examined with respect to various ice cloud parameters. Uncertainties in the retrieval of the SSRB due to inadequate knowledge of various ice cloud parameters are evaluated thoroughly. The uncertainty study is concerned with both pure ice clouds and multiphase clouds (ice cloud above water cloud). According to the magnitudes of errors in the SSRB retrieval caused by different input variables, parameterized correction terms were introduced. If the input variables are known accurately, errors in the retrieval of the SSRB under a wide range of ice cloud conditions are expected to diminish substantially, to less than 10 W m−2 for 91% of the simulated ice cloud cases. In comparison, the same accuracy may be attained for only 19% of the retrievals for the same ice cloud cases using the retrieval algorithm designed for non-ice-cloud conditions.
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  • 93
    Publication Date: 2020-08-04
    Description: North Atlantic synoptic-scale processes are analyzed by bandpassing 6-hourly NCEP–NCAR reanalysis data (1958–98) for several synoptic ranges corresponding to ultrahigh-frequency variability (0.5–2 days), synoptic-scale variability (2–6 days), slow synoptic processes (6–12 days), and low-frequency variability (12–30 days). Climatological patterns of the intensity of synoptic processes are not collocated for different ranges of variability, especially in the lower troposphere. Intensities of synoptic processes demonstrate opposite trends between the North American coast and in the northeast Atlantic. Although north of 40°N the intensity of ultrahigh-frequency variability and synoptic-scale processes show similar interannual variability, further analysis indicates that secular changes, and decadal-scale and interannual variability in the intensities of synoptic processes may not be necessarily consistent for different synoptic timescales. Magnitudes of winter ultrahigh-frequency variability are highly correlated with the intensity of synoptic-scale processes in the 1960s and early 1970s. However, they show little agreement with each other during the last two decades, pointing to the remarkable change in atmospheric variability over the North Atlantic in late 1970s. North Atlantic ultrahigh-frequency variability in winter is highly correlated with surface temperature gradient anomalies in the Atlantic–American sector. These gradients are computed from the merged fields of SST and surface temperature over the continent. They demonstrate a dipolelike pattern associated with the North American coast on one hand, with the subpolar SST front and continental Canada on the other. High-frequency variability and its synoptic counterpart demonstrate different relationships with the North Atlantic Oscillation. Reliability of these results and their sensitivity to the filtering procedures are addressed by comparison to radiosonde data and application of alternative filters.
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  • 94
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 32 (2). pp. 401-410.
    Publication Date: 2019-09-23
    Description: Turbulent fluxes of momentum and sensible heat were estimated from sonic anemometer measurements gathered over the Labrador Sea during a winter cruise of the R/V Knorr. The inertial dissipation method was used to calculate turbulent fluxes of momentum. The resulting drag coefficients agree well with earlier findings. Sensible heat fluxes were computed using both cross-correlation and inertial dissipation techniques. There is good agreement between results from both methods, although there is more scatter in the correlation fluxes than the dissipation fluxes. The inertial dissipation method gives reasonable results even under conditions of high wind speeds and low air temperatures, which combined with the relatively warm sea surface temperatures lead to sensible heat fluxes of several hundred watts per square meter. Sensible heat fluxes obtained from the sonic anemometer measurements agree well with bulk turbulent fluxes according to the formulation of Isemer and Hasse.
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  • 95
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    Nature Publishing Group
    In:  Nature Geoscience, 417 . pp. 848-851.
    Publication Date: 2017-02-28
    Description: A key question in ecology is which factors control species diversity in a community1, 2, 3. Two largely separate groups of ecologists have emphasized the importance of productivity or resource supply, and consumers or physical disturbance, respectively. These variables show unimodal relationships with diversity when manipulated in isolation4, 5, 6, 7, 8. Recent multivariate models9, 10, however, predict that these factors interact, such that the disturbance–diversity relationship depends on productivity, and vice versa. We tested these models in marine food webs, using field manipulations of nutrient resources and consumer pressure on rocky shores of contrasting productivity. Here we show that the effects of consumers and nutrients on diversity consistently depend on each other, and that the direction of their effects and peak diversity shift between sites of low and high productivity. Factorial meta-analysis of published experiments confirms these results across widely varying aquatic communities. Furthermore, our experiments demonstrate that these patterns extend to important ecosystem functions such as carbon storage and nitrogen retention. This suggests that human impacts on nutrient supply11 and food-web structure12, 13 have strong and interdependent effects on species diversity and ecosystem functioning, and must therefore be managed together.
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  • 96
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    Nature Publishing Group
    In:  Nature, 417 . pp. 487-488.
    Publication Date: 2017-03-07
    Description: BOOK REVIEWED: Plate Tectonics: An Insider's History of the Modern Theory of the Earth / edited by Naomi Oreskes Westview Press: 2001. 448 pp.
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  • 97
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    AMS (American Meteorological Society)
    In:  Journal of Atmospheric and Oceanic Technology, 19 (5). pp. 794-807.
    Publication Date: 2017-01-25
    Description: Lowered acoustic Doppler current profilers (LADCPs) have matured from an experimental instrument to an operational hydrographic tool to study ocean dynamics. The data processing, however, is still in a rather primitive state. First, a method to estimate bottom-track velocities using the standard water profile data was developed. Then inverse solutions are presented that enhance the standard data processing by adding external constraints such as bottom-referenced velocity profiles. Depending on the depth of the profile and the ADCP range the inclusion of bottom-track data can reduce the local velocity errors by a significant factor. The least squares framework also allows for simplified error analysis of the LADCP system and some of the trade-offs are discussed.
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  • 98
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 32 (8). pp. 2205-2235.
    Publication Date: 2018-04-10
    Description: Zonal transports of North Atlantic Deep Water (NADW) in the South Atlantic are determined. For this purpose the circulation of intermediate and deep water masses is established on the basis of hydrographic sections from the World Ocean Circulation Experiment (WOCE) and some pre-WOCE sections, using temperature, salinity, nutrients, and anthropogenic tracers. Multiple linear regression is applied to infer missing parameters in the bottle dataset. A linear box-inverse model is used for a set of closed boxes given by sections and continental boundaries. After performing a detailed analysis of water mass distribution, 11 layers are prescribed. Neutral density surfaces are selected as layer interfaces, thus improving the description of water mass distribution in the transition between the subtropical and subpolar latitudes. Constraints for the inverse model include integral meridional salt and phosphorus transports, overall salt and silica conservation, and transports from moored current meter observations. Inferred transport numbers for the mean meridional thermohaline overturning are given. Persistent zonal NADW transport bands are found in the western South Atlantic, in particular eastward flow of relatively new NADW between 20° and 25°S and westward flow of older NADW to the north of this latitude range. The axis of the eastward transport band corresponds to the core of property distributions in this region, suggesting Wüstian flow. Part of the eastward flow appears to cross the Mid-Atlantic Ridge at the Rio de Janeiro Fracture Zone. Results are compared qualitatively with deep float observations and results from general circulation models
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  • 99
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    Unknown
    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 32 . pp. 573-584.
    Publication Date: 2020-08-04
    Description: Fifteen profiling floats were injected into the deep boundary current off Labrador. They were ballasted to drift in the core depth of Labrador Sea Water (LSW) at 1500-m depth and were deployed in two groups during March and July/August 1997. Initially, for about three months, the floats were drifting within the boundary current, and the flow vectors were used to determine the mean horizontal structure of the Deep Labrador Current, which was found to be about 100 km wide with an average core speed of 18 cm s−1. North of Flemish Cap the boundary current encounters complicated topography around “Orphan Knoll,” and there the LSW outflow splits up into different routes. One obvious LSW path is eastward through the Charlie Gibbs Fracture Zone and another route is a narrow recirculation toward the central Labrador Sea. A surprising result was that none of the floats were able to follow the boundary current southward to the Grand Banks area and exit into the subtropics. Trajectories and temperature profiles of the eastward drifting floats indicate the importance of the North Atlantic Current for dispersing the floats, even at the level of LSW.
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  • 100
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 32 . pp. 1567-1573.
    Publication Date: 2020-08-04
    Description: The analysis of high-resolution oceanographic data referring to velocity measurements carried out by means of a vessel-mounted acoustic Doppler current profiler on 12 November 2000 in the equatorial Atlantic, at 44°W between 4.5° and 6°N, reveals the presence of three large-amplitude internal solitary waves superimposed on the velocity field associated with the North Equatorial Countercurrent (NECC). These waves were found in the deep ocean, more than 500 km off the continental shelf and far from regions of topographic variations. They propagated toward the north-northeast, strongly inclined with respect to the main axis of the NECC and perpendicular to the Brazilian shelf, as well as to the North Brazil Current, and were characterized by maximum horizontal velocities of about 2 m s−1 and maximum vertical velocities of about 20 cm s−1. The large magnitudes of the measured velocities indicate that the observed waves represent disturbances evolving in a strongly stratified ocean. The distance separating the waves (about 70 km) indicates that the observed features cannot be considered as elements of a single train of internal solitary waves. The waves consist, instead, of truly disconnected, pulselike intense solitary disturbances. This behavior, which strongly differs from that typically observed for trains of tidally generated internal solitary waves, indicates that different mechanisms were possibly involved in their generation and/or evolution.
    Type: Article , PeerReviewed
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