scholarly journals High-resolution genetic analysis reveals extensive gene flow within the jellyfishPelagia noctiluca(Scyphozoa) in the North Atlantic and Mediterranean Sea

2015 ◽  
Vol 117 (2) ◽  
pp. 252-263 ◽  
Author(s):  
Fergal Glynn ◽  
Jonathan D. R. Houghton ◽  
Thomas Bastian ◽  
Thomas K. Doyle ◽  
Verónica Fuentes ◽  
...  
Keyword(s):  
Gene Flow ◽  
High Resolution ◽  
Genetic Analysis ◽  
Mediterranean Sea ◽  
North Atlantic ◽  
The North ◽  
The North Atlantic

7000 years of paleostorm activity in the NW Mediterranean Sea in response to Holocene climate events

2012 ◽  
Vol 77 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Pierre Sabatier ◽  
Laurent Dezileau ◽  
Christophe Colin ◽  
Louis Briqueu ◽  
Frédéric Bouchette ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
North Atlantic ◽  
Clay Mineralogy ◽  
Mediterranean Coast ◽  
Ice Age ◽  
Storm Activity ◽  
The North ◽  
Nw Mediterranean ◽  
The North Atlantic ◽  
Nw Mediterranean Sea

A high-resolution record of paleostorm events along the French Mediterranean coast over the past 7000 years was established from a lagoonal sediment core in the Gulf of Lions. Integrating grain size, faunal analysis, clay mineralogy and geochemistry data with a chronology derived from radiocarbon dating, we recorded seven periods of increased storm activity at 6300–6100, 5650–5400, 4400–4050, 3650–3200, 2800–2600, 1950–1400 and 400–50 cal yr BP (in the Little Ice Age). In contrast, our results show that the Medieval Climate Anomaly (1150–650 cal yr BP) was characterised by low storm activity.The evidence for high storm activity in the NW Mediterranean Sea is in agreement with the changes in coastal hydrodynamics observed over the Eastern North Atlantic and seems to correspond to Holocene cooling in the North Atlantic. Periods of low SSTs there may have led to a stronger meridional temperature gradient and a southward migration of the westerlies. We hypothesise that the increase in storm activity during Holocene cold events over the North Atlantic and Mediterranean regions was probably due to an increase in the thermal gradient that led to an enhanced lower tropospheric baroclinicity over a large Central Atlantic-European domain.

North Atlantic Oscillation-related impacts on precipitation over the Italian Peninsula during the 1979-2020 period

2021 ◽  
Author(s):  
Paula Lorenzo Sánchez ◽  
Leonardo Aragão
Keyword(s):  
High Resolution ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Mediterranean Region ◽  
Italian Peninsula ◽  
The North ◽  
Nao Index ◽  
The North Atlantic ◽  
The Mediterranean ◽  
Resolution Dataset

<p>The North Atlantic Oscillation (NAO) has been widely recognized as one of the main patterns of atmospheric variability over the northern hemisphere, helping to understand variations on the North Atlantic Jet (NAJ) position and its influence on storm-tracks, atmospheric blocking and Rossby Wave breaking. Among several relevant teleconnection patterns identified through different timescales, the most prominent ones are found for northern Europe during winter months, when positive (negative) phases of NAO are related to wetter (drier) conditions. Although it is not well defined yet, an opposite connection is observed for the Mediterranean region, where negative NAO values are often associated with high precipitation. Therefore, the main goal of this study is to identify which regions and periods of the year are the most susceptible to abundant NAO-related precipitation throughout the Italian Peninsula. For doing so, the last 42 years period (1979-2020) was analysed using the Fifth Generation ECMWF Atmospheric ReAnalysis of the Global Climate (ERA5). The NAO index was calculated using the Mean Sea Level Pressure (MSLP) extracted from the nearest gridpoints to Reykjavik, Ponta Delgada, Lisbon and Gibraltar, with a time resolution of one hour and horizontal spatial resolution of 0.25ºx0.25º. Both NAO index and MSLP time series were validated for different timescales (hourly, daily, monthly and seasonal) using the Automated Surface Observing System data and the Climatic Research Unit (CRU) high-resolution dataset (based on measured data). High correlations, ranging from 0.92 to 0.98, were found for all stations, timescales and evaluated parameters. To quantify the influence of NAO over the Mediterranean region, the monthly averaged ERA5 ‘total precipitation’ data over the Italian Peninsula [35-48º N; 5-20º E] were used. As expected, the results concerning NAO x Precipitation presented the best correlations when analysed monthly, confirming some of the already known NAO signatures over the Italian Peninsula: higher correlations during winter and over the Tyrrhenian coast, and lower correlations during summer and over the Apennines, the Adriatic Sea and the Ionian Sea. On the other hand, the precipitation over the Alps and the Tunisian coast presented a remarkable signature of positive NAO values that, despite a lower statistical significance (85-90%), is in agreement with recent findings of observational studies. In addition, significant negative correlations were identified for the spring and autumn months over the Tyrrhenian area. Among those, the high correlations found during May are particularly interesting, as they follow the behaviour described in recent studies performed using the same high-resolution dataset (ERA5), which have identified an increased number of cyclones over the Mediterranean during this month. This connection suggests that NAO could also be used to explore the potential penetration of the North Atlantic depressions into the Mediterranean Basin. </p><p>Keywords: NAO; Teleconnections; ERA5; ReAnalysis; Mediterranean; Climatology.</p>

scholarly journals Effects of High Resolution and Spinup Time on Modeled North Atlantic Circulation

2019 ◽  
Vol 49 (5) ◽  
pp. 1159-1181 ◽  
Author(s):  
Christopher Danek ◽  
Patrick Scholz ◽  
Gerrit Lohmann
Keyword(s):  
High Resolution ◽  
North Atlantic ◽  
Horizontal Resolution ◽  
Quasi Equilibrium ◽  
Low Resolution ◽  
The North ◽  
Resolution Model ◽  
High Horizontal Resolution ◽  
High Resolution Model ◽  
The North Atlantic

AbstractThe influence of a high horizontal resolution (5–15 km) on the general circulation and hydrography in the North Atlantic is investigated using the Finite Element Sea Ice–Ocean Model (FESOM). We find a stronger shift of the upper-ocean circulation and water mass properties during the model spinup in the high-resolution model version compared to the low-resolution (~1°) control run. In quasi equilibrium, the high-resolution model is able to reduce typical low-resolution model biases. Especially, it exhibits a weaker salinification of the North Atlantic subpolar gyre and a reduced mixed layer depth in the Labrador Sea. However, during the spinup adjustment, we see that initially improved high-resolution features partially reduce over time: the strength of the Atlantic overturning and the path of the North Atlantic Current are not maintained, and hence hydrographic biases known from low-resolution ocean models return in the high-resolution quasi-equilibrium state. We identify long baroclinic Rossby waves as a potential cause for the strong upper-ocean adjustment of the high-resolution model and conclude that a high horizontal resolution improves the state of the modeled ocean but the model integration length should be chosen carefully.

Lagrangian data in a high-resolution numerical simulation of the North Atlantic

2001 ◽  
Vol 29 (1-4) ◽  
pp. 157-176 ◽  
Author(s):  
Zulema D Garraffo ◽  
Arthur J Mariano ◽  
Annalisa Griffa ◽  
Carmela Veneziani ◽  
Eric P Chassignet
Keyword(s):  
Numerical Simulation ◽  
High Resolution ◽  
North Atlantic ◽  
The North ◽  
The North Atlantic ◽  
Lagrangian Data

scholarly journals The North Atlantic Subpolar Gyre in Four High-Resolution Models

2005 ◽  
Vol 35 (5) ◽  
pp. 757-774 ◽  
Author(s):  
A. M. Treguier ◽  
S. Theetten ◽  
E. P. Chassignet ◽  
T. Penduff ◽  
R. Smith ◽  
...  
Keyword(s):  
High Resolution ◽  
North Atlantic ◽  
Ocean Model ◽  
Quantitative Comparison ◽  
Subpolar Gyre ◽  
Reykjanes Ridge ◽  
The North ◽  
North Atlantic Subpolar Gyre ◽  
The North Atlantic ◽  
High Resolution Models

Abstract The authors present the first quantitative comparison between new velocity datasets and high-resolution models in the North Atlantic subpolar gyre [1/10° Parallel Ocean Program model (POPNA10), Miami Isopycnic Coordinate Ocean Model (MICOM), ⅙° Atlantic model (ATL6), and Family of Linked Atlantic Ocean Model Experiments (FLAME)]. At the surface, the model velocities agree generally well with World Ocean Circulation Experiment (WOCE) drifter data. Two noticeable exceptions are the weakness of the East Greenland coastal current in models and the presence in the surface layers of a strong southwestward East Reykjanes Ridge Current. At depths, the most prominent feature of the circulation is the boundary current following the continental slope. In this narrow flow, it is found that gridded float datasets cannot be used for a quantitative comparison with models. The models have very different patterns of deep convection, and it is suggested that this could be related to the differences in their barotropic transport at Cape Farewell. Models show a large drift in watermass properties with a salinization of the Labrador Sea Water. The authors believe that the main cause is related to horizontal transports of salt because models with different forcing and vertical mixing share the same salinization problem. A remarkable feature of the model solutions is the large westward transport over Reykjanes Ridge [10 Sv (Sv ≡ 106 m3 s−1) or more].

Second reply to the comment by Romero and Kannada on “Genetic analysis of 16th-century whale bones prompts a revision of the impact of Basque whaling on right and bowhead whales in the western North Atlantic”Appears in Can. J. Zool. 84(7): 1059–1065.

2008 ◽  
Vol 86 (1) ◽  
pp. 76-79 ◽  
Author(s):  
Jeff W. Higdon
Keyword(s):  
Genetic Analysis ◽  
North Atlantic ◽  
16Th Century ◽  
Bowhead Whales ◽  
Potential Value ◽  
The North ◽  
The Pacific ◽  
History Of ◽  
The North Atlantic ◽  
The Impact

The comments by A. Romero and S. Kannada (2006. Can. J. Zool. 84: 1059–1065) provide a brief summary of North Atlantic whaling history as a critique of T. Rastogi et al. (2004. Can. J. Zool. 82: 1647–1654) . However, they fall far short of providing an accurate review of whaling history in this region. The authors present a number of factual errors, misuse several key sources, and make significant omissions, ultimately defeating the purpose of providing information to biologists, managers, and historians. In this comment I highlight the mistakes in their representation of the history of North Atlantic whaling for bowhead whales ( Balaena mysticetus L., 1758). There are unacceptable errors for most nations covered, and for American whaling in particular. The authors assert that over 30 000 bowhead whales were landed by Yankee whalers in the North Atlantic when the vast majority were in fact taken on the Pacific grounds. Although a summary of whaling history is an admirable goal and of potential value, it is unfortunate that the authors missed such an opportunity by failing to adequately research this topic, failing to include important citations, and by including sources that do not provide the information indicated. Providing a whaling summary with such errors and omissions only adds further confusion to an already confusing theme.

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