scholarly journals The paradox of constant oceanic plastic debris: evidence for evolved microbial biodegradation?

2017 ◽  
Author(s):  
Ricard Solé ◽  
Ernest Fontich ◽  
Blai Vidiella ◽  
Salva Duran-Nebreda ◽  
Raúl Montañez ◽  
...  
Keyword(s):  
North Atlantic ◽  
Nonlinear Coupling ◽  
Global Studies ◽  
Two Dimensional ◽  
Plastic Debris ◽  
The North ◽  
Microbial Biodegradation ◽  
The North Atlantic ◽  
The Difference ◽  
Microbial Model

Although the presence of vast amounts of plastic in the open ocean has generated great concern due to its potential ecological consequences, recent studies reveal that its measured abundance is much smaller than expected. Regional and global studies indicate that the difference between expected and actual estimates is enormous, suggesting that a large part of the plastic has been degraded by either physical and biotic processes. A paradoxical observation is the lack of a trend in plastic accumulation found in the North Atlantic Subtropical Gyre, despite the rapid increase in plastic production and disposal. In this paper we show, using mathematical and computer models, that this observation could be explained by the nonlinear coupling between plastic (as a resource) and an evolved set of organisms (the consumers) capable of degrading it. The result is derived using two different resource-consumer mathematical approaches as well as a spatially-dependent plastic-microbial model incorporating a minimal hydrodynamical coupling with a two-dimensional fluid. The potential consequences of the evolution of marine plastic garbage and its removal are outlined.

Le controle du socle dans l'évolution de la sedimentation en Manche occidentale apres le Paléozoïque

1975 ◽  
Vol 279 (1288) ◽  
pp. 137-143 ◽  
Keyword(s):  
North Atlantic ◽  
Transverse Direction ◽  
Longitudinal Direction ◽  
The West ◽  
The North ◽  
The North Atlantic ◽  
The Difference ◽  
Cenozoic Sediments ◽  
Two Sides

The estimates of the thickness of the Mesozoic and Cenozoic sediments found in the western Channel show that the deposition of these sediments was controlled by two independent processes. (1) In the longitudinal direction, the displacement of maximum sedimentation, from east to west is entirely dependent on the opening of the North Atlantic. (2) In a transverse direction, it is probable that the difference of subsidence between the two sides of the Aurigny—Ouessant fault originated from the fracturing of the original Atlantic rift in the Western Approaches. Transverse compressions and extensions have disturbed the continual depression of the Channel towards the west.

A Unified Nonlinear Multiscale Interaction Model of Pacific–North American Teleconnection Patterns

2020 ◽  
Vol 77 (4) ◽  
pp. 1387-1414
Author(s):  
Dehai Luo ◽  
Yao Ge ◽  
Wenqi Zhang ◽  
Aiguo Dai
Keyword(s):  
North Atlantic ◽  
North American ◽  
Wave Train ◽  
Interaction Model ◽  
Energy Dispersion ◽  
Pacific North American ◽  
The North ◽  
The North Atlantic ◽  
The Difference ◽  
Multiscale Interaction

Abstract In this paper, reanalysis data are first analyzed to reveal that the individual negative (positive)-phase Pacific–North American pattern (PNA) or PNA− (PNA+) has a lifetime of 10–20 days, is characterized by strong (weak) westerly jet stream meanders, and exhibits clear wave train structures, whereas the PNA− with rapid retrogression tends to have longer lifetime and larger amplitude than the PNA+ with slow retrogression. In contrast, the wave train structure of the North Atlantic Oscillation (NAO) is less distinct, and the positive (negative)-phase NAO shows eastward (westward) movement around a higher latitude than the PNA. Moreover, it is found that the PNA wave train occurs under a larger background meridional potential vorticity gradient (PVy) over the North Pacific than that over the North Atlantic for the NAO. A unified nonlinear multiscale interaction (UNMI) model is then developed to explain why the PNA as a nonlinear wave packet has such characteristics and its large difference from the NAO. The model results reveal that the larger background PVy for the PNA (due to its location at lower latitudes) leads to its larger energy dispersion and weaker nonlinearity than the NAO, thus explaining why the PNA (NAO) is largely a linear (nonlinear) process with a strong (weak) wave train structure, though it is regarded as a nonlinear initial-value problem. The smaller PVy for the PNA− than for the PNA+ leads to lower energy dispersion and stronger nonlinearity for PNA−, which allows it to maintain larger amplitude and have a longer lifetime than the PNA+. Thus, the difference in the background PVy is responsible for the asymmetry between the two phases of PNA and the difference between the PNA and NAO.

scholarly journals Variations in the difference between mean sea level measured either side of Cape Hatteras and their relation to the North Atlantic Oscillation

2016 ◽  
Vol 49 (7-8) ◽  
pp. 2451-2469 ◽  
Author(s):  
P. L. Woodworth ◽  
M. Á. Morales Maqueda ◽  
W. R. Gehrels ◽  
V. M. Roussenov ◽  
R. G. Williams ◽  
...  
Keyword(s):  
North Atlantic Oscillation ◽  
Sea Level ◽  
North Atlantic ◽  
Mean Sea Level ◽  
The North ◽  
Cape Hatteras ◽  
The North Atlantic ◽  
The Difference ◽  
The North Atlantic Oscillation

scholarly journals Interannual Variability of High-Wind Occurrence over the North Atlantic*

2011 ◽  
Vol 24 (24) ◽  
pp. 6515-6527 ◽  
Author(s):  
Xuhua Cheng ◽  
Shang-Ping Xie ◽  
Hiroki Tokinaga ◽  
Yan Du
Keyword(s):  
Interannual Variability ◽  
North Atlantic ◽  
Gulf Stream ◽  
Storm Track ◽  
Surface Air Temperature ◽  
High Wind ◽  
The North ◽  
The North Atlantic ◽  
The Difference ◽  
The North Atlantic Oscillation

Abstract Interannual variability of high-wind occurrence over the North Atlantic is investigated based on observations from the satellite-borne Special Sensor Microwave Imager (SSM/I). Despite no wind direction being included, SSM/I data capture major features of high-wind frequency (HWF) quite well. Climatology maps show that HWF is highest in winter and is close to zero in summer. Remarkable interannual variability of HWF is found in the vicinity of the Gulf Stream, over open sea south of Iceland, and off Cape Farewell, Greenland. On interannual scales, HWF south of Iceland has a significant positive correlation with the North Atlantic Oscillation (NAO). An increase in the mean westerlies and storm-track intensity during a positive NAO event cause HWF to increase in this region. In the vicinity of the Gulf Stream, HWF is significantly correlated with the difference between sea surface temperature and surface air temperature (SST − SAT), indicative of the importance of atmospheric instability. Cross-frontal wind and an SST gradient are important for the instability of the marine atmospheric boundary layer on the warm flank of the SST front. Off Cape Farewell, high wind occurs in both westerly and easterly tip jets. Quick Scatterometer (QuikSCAT) data show that variability in westerly (easterly) HWF off Cape Farewell is positively (negatively) correlated with the NAO.

The Economics of the North Atlantic Air Traffic System

1986 ◽  
Vol 39 (1) ◽  
pp. 103-109 ◽  
Author(s):  
V. W. Attwooll
Keyword(s):  
North Atlantic ◽  
Air Traffic ◽  
Track Structure ◽  
Traffic System ◽  
The North ◽  
Parallel Track ◽  
The Hours ◽  
The North Atlantic ◽  
The Difference ◽  
A Current

1. INTRODUCTION. The North Atlantic air traffic system is the busiest and most important long-range system in operation today with a current total of 127 000 flights“annum. The combined effects of the total flight time and the difference in time zones on either side of the Atlantic makes it desirable for most passengers to fly westward in the day-time. Conversely, it is most convenient (or least inconvenient!) to fly eastbound during the hours of darkness. Thus the Atlantic traffic system is strongly tidal with the flow predominantly (though not entirely) westbound during the day and eastbound overnight. Currently the central core of the traffic in the busiest hours is organised into a parallel track structure – the Organized Track Structure (OTS), though nearly half the aircraft operate so-called random routes clear of the OTS.

A Stochastic Model for the Spatial Structure of Annular Patterns of Variability and the North Atlantic Oscillation

2005 ◽  
Vol 18 (12) ◽  
pp. 2102-2118 ◽  
Author(s):  
Edwin P. Gerber ◽  
Geoffrey K. Vallis
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Zonal Wind ◽  
Stochastic Models ◽  
Two Dimensional ◽  
Eof Analysis ◽  
The North ◽  
The North Atlantic ◽  
The One ◽  
The North Atlantic Oscillation

Abstract Meridional dipoles of zonal wind and geopotential height are found extensively in empirical orthogonal function (EOF) analysis and single-point correlation maps of observations and models. Notable examples are the North Atlantic Oscillation and the so-called annular modes (or the Arctic Oscillation). Minimal stochastic models are developed to explain the origin of such structure. In particular, highly idealized, analytic, purely stochastic models of the barotropic, zonally averaged zonal wind and of the zonally averaged surface pressure are constructed, and it is found that the meridional dipole pattern is a natural consequence of the conservation of zonal momentum and mass by fluid motions. Extension of the one-dimensional zonal wind model to two-dimensional flow illustrates the manner in which a local meridional dipole structure may become zonally elongated in EOF analysis, producing a zonally uniform EOF even when the dynamics is not particularly zonally coherent on hemispheric length scales. The analytic system then provides a context for understanding the existence of zonally uniform patterns in models where there are no zonally coherent motions. It is also shown how zonally asymmetric dynamics can give rise to structures resembling the North Atlantic Oscillation. Both the one- and two-dimensional results are manifestations of the same principle: given a stochastic system with a simple red spectrum in which correlations between points in space (or time) decay as the separation between them increases, EOF analysis will typically produce the gravest mode allowed by the system’s constraints. Thus, grave dipole patterns can be robustly expected to arise in the statistical analysis of a model or observations, regardless of the presence or otherwise of a dynamical mode.

Measurement of NOx and Ozone over the North Atlantic Ocean.

2020 ◽  
Author(s):  
James Lee ◽  
Freya Squires ◽  
Simone Andersen ◽  
Jim Hopkins ◽  
Dominika Pasternak ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Atmospheric Measurements ◽  
The North ◽  
Research Aircraft ◽  
Natural Emissions ◽  
The North Atlantic ◽  
The Difference ◽  
The Uk

<p>Tropospheric ozone (O<sub>3</sub>) can adversely affect human health and environmental ecosystems and it is therefore vitally important to understand its formation pathways from both natural and anthropogenic precursors. Background O<sub>3</sub> levels in the Northern Hemisphere have increased by more than a factor of two over the last century and it is believed that this increase is strongly tied to the increase in and distribution of anthropogenic nitrogen oxide (N0<sub>x</sub>) emissions. This is important as the changing level of O<sub>3</sub> in the background troposphere impacts the ability of countries downwind to achieve their air quality standards.</p><p>As part of the NERC funded North Atlantic Climate System Integrated Study (ACSiS) and Methane Observations and Yearly Assessments (MOYA) projects, multiple research flights have taken place over the North Atlantic Ocean, spanning an area from 55<sup>o</sup>N to 12<sup>o</sup>N and 8<sup>o</sup>W to 25<sup>o</sup>W using the UK’s large research aircraft (The Facility for Airborne Atmospheric Measurements – FAAM). Flights took place in all seasons from 2017 – 2020. A variety of gas and aerosol measurements were made, including NO<sub>x</sub>, O<sub>3, </sub>CO and a range of VOCs and an overview of the data is presented here. Measurements were taken in a range of air masses, including biomass burning outflow from West Africa, urban outflow from Europe and emissions from the busy shipping lanes to the West of Portugal.</p><p>Data was analysed to assess O<sub>3</sub> formation from the different emission sources, in particular examining the difference between anthropogenic and natural emissions. In addition, the output of regional chemistry models is compared to the data in order to assess the performance of the models in predicting O<sub>3</sub> and its precursors.</p>

The North Atlantic Organized Track Structure

1982 ◽  
Vol 35 (3) ◽  
pp. 497-499 ◽  
Author(s):  
V. W. Attwooll
Keyword(s):  
North Atlantic ◽  
General Pattern ◽  
Local Times ◽  
Main Stream ◽  
Diurnal Pattern ◽  
Traffic System ◽  
The North ◽  
Transit Times ◽  
The North Atlantic ◽  
The Difference

The first point to note about the North Atlantic air traffic system is the diurnal pattern of flow. This is strongly tidal, with westbound flow predominant during daylight hours and eastbound flow overnight. There is some traffic which flows against the main stream, particularly during the day, but the strong tendency for one-way traffic results from the difference in local times on opposite sides of the ocean, together with the transit times of flight at current speeds. This means that the general pattern will probably persist, unless and until aircraft speeds change radically.

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