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| Registros recuperados: 13 | |
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| Cronin, Tm; Dwyer, Gs; Kamiya, T; Schwede, S; Willard, Da. |
| We present paleoclimate evidence for rapid (< 100 years) shifts of similar to 2-4 degreesC in Chesapeake Bay (CB) temperature similar to 2100, 1600, 950, 650, 400 and 150 years before present (years BP) reconstructed from magnesium/calcium (Mg/Ca) paleothermometry. These include large temperature excursions during the Little Ice Age (similar to 1400-1900 AD) and the Medieval Warm Period (similar to 800-1300 AD) possibly related to changes in the strength of North Atlantic thermohaline circulation (THC). Evidence is presented for a long period of sustained regional and North Atlantic-wide warmth with low-amplitude temperature variability between similar to450. and 1000 AD. In addition to centennial-scale temperature shifts, the existence of numerous... |
| Tipo: Text |
Palavras-chave: Paleoclimatology; Holocene; Medieval Warm Period; Little Ice Age; 20th century climate; North Atlantic Oscillation. |
| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/00225/33648/32092.pdf |
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| Thierry, Virginie; De Boisseson, Eric; Mercier, Herle. |
| Combining hydrographic data from the OVIDE (Observatoire de la Variabilité Interannuelle à Decennale/Observatory of the Interannual to Decadal Variability) section (Greenland-Portugal) with Argo and historical CTD data over the period 19902006, we estimate the variability of the core properties of a variety of Subpolar Mode Water (SPMW) observed on the eastern flank of the Reykjanes Ridge. This SPMW acquires its core properties in the winter mixed layer along the eastern side of the Reykjanes Ridge. We find that the February sea surface temperature along the ridge is a proxy for its core temperature. The sources of this mode water are water masses advected by the mean cyclonic circulation in the Iceland Basin. A density compensated tendency for cooling... |
| Tipo: Text |
Palavras-chave: North Atlantic Oscillation; Subpolar mode water; North Atlantic Ocean. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3487.pdf |
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| Fromentin, Jean-marc. |
| In the recent past, it has been put forward that recruitment of the North Atlantic albacore, East Atlantic bluefin tuna and North Atlantic swordfish could be related to the North AtlanticOscillation (NAO). In this document, the biological processes behind the NAO/recruitmentrelationship are further investigated. Then, the possible relationship between the East Atlanticbluefin tuna recruitment was re-investigated. The linear relationship appeared to be only due to the low frequency signal, both BFT recruitment and NAO displaying a pseudo-cyclic upwardtrend, but year-to-year fluctuations were not synchronous. The superposed epoch analysis, thatwas conducted to test for possible non-linear and non-monotonous relationship did not reveal any clear connection.... |
| Tipo: Text |
Palavras-chave: North Atlantic Oscillation; Recruitment; Bluefin; Albacore; Swordfish; Migration patterns; Time series; Spatially disaggregated data. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00194/30498/28908.pdf |
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| Kandiano, Evgenia S.; Bauch, Henning A.; Fahl, Kirsten; Helmke, Jan P.; Roehl, Ursula; Perez-folgado, Marta; Cacho, Isabel. |
| Temporal and spatial patterns in eastern North Atlantic sea-surface temperatures (SST) were reconstructed for marine isotope stage (MIS) 11c using a submeridional transect of five sediment cores. The SST reconstructions are based on planktic foraminiferal abundances and alkenone indices, and are supported by benthic and planktic stable isotope measurements, as well as by ice-rafted debris content in polar and middle latitudes. Additionally, the larger-scale dynamics of the precipitation regime over northern Africa and the western Mediterranean region was evaluated from iron concentrations in marine sediments off NW Africa and planktic delta C-13 in combination with analysis of planktic foraminiferal abundances down to the species level in the Mediterranean... |
| Tipo: Text |
Palavras-chave: Eastern North Atlantic; Stage 11; North Atlantic Oscillation; Foraminiferal sea surface temperatures; Alkenone sea surface temperatures. |
| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00265/37654/36976.pdf |
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| Boessenkool, K. P.; Hall, I. R.; Elderfield, H.; Yashayaev, I.. |
| Variations in the near-bottom flow speed of Iceland-Scotland Overflow Water (ISOW) are documented in a 230-year-long deep-sea sediment record from the eastern flank of Reykjanes Ridge in the subpolar North Atlantic at (sub) decadal time scales. For recent decades, the ISOW palaeocurrent reconstructions show similarities with observational hydrographic data. Furthermore, recent ISOW flow changes fall mostly within the range of its variability of the past 230 years. The record also reveals a hitherto unrecognized coupling of deep flow speeds in the subpolar North Atlantic with the North Atlantic Oscillation (NAO) index, with more (less) vigorous ISOW flow during negative (positive) phases of the NAO. Our results suggest that the changes in ISOW vigor are... |
| Tipo: Text |
Palavras-chave: Deep ocean circulation; North Atlantic Oscillation; Drift sediments. |
| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00235/34646/33007.pdf |
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| Arzel, Olivier; Huck, Thierry. |
| Atmospheric stochastic forcing associated with the North Atlantic Oscillation (NAO) and intrinsic ocean modes associated with the large-scale baroclinic instability of the North Atlantic Current (NAC) are recognized as two strong paradigms for the existence of the Atlantic Multidecadal Oscillation (AMO). The degree to which each of these factors contribute to the low-frequency variability of the North Atlantic is the central question in this paper. This issue is addressed here using an ocean general circulation model run under a wide range of background conditions extending from a super-critical regime where the oceanic variability spontaneously develops in the absence of any atmospheric noise forcing to a damped regime where the variability requires some... |
| Tipo: Text |
Palavras-chave: Instability; Rossby waves; Climate variability; Interdecadal variability; Multidecadal variability; North Atlantic Oscillation. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00599/71138/69452.pdf |
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| Keller, Kathrin M.; Joos, Fortunat; Raible, Christoph C.; Cocco, Valentina; Froelicher, Thomas L.; Dunne, John P.; Gehlen, Marion; Bopp, Laurent; Orr, James C.; Tjiputra, Jerry; Heinze, Christoph; Segschneider, Joachim; Roy, Tilla; Metzl, Nicolas. |
| Climate modes such as the North Atlantic Oscillation (NAO), representing internal variability of the climate system, influence the ocean carbon cycle and may mask trends in the sink of anthropogenic carbon. Here, utilising control runs of six fully coupled Earth System Models, the response of the ocean carbon cycle to the NAO is quantified. The dominating response, a seesaw pattern between the subtropical gyre and the subpolar Northern Atlantic, is instantaneous (<3 months) and dynamically consistent over all models and with observations for a range of physical and biogeochemical variables. All models show asymmetric responses to NAO+ and NAO− forcing, implying non-linearity in the connection between NAO and the ocean carbon cycle. However, model... |
| Tipo: Text |
Palavras-chave: North Atlantic Oscillation; Carbon cycle; Ocean biogeochemistry; Climate modeling; Ocean-atmosphere interaction. |
| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00140/25166/23272.pdf |
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| Rouyer, Tristan; Fromentin, Jean-marc; Menard, Felix; Calzelles, B; Briand, K; Pianet, R; Planque, Benjamin; Stenseth, N. |
| The patterns of variations in fisheries time series are known to result from a complex combination of species and fisheries dynamics all coupled with environmental forcing (including climate, trophic interactions, etc.). Disentangling the relative effects of these factors has been a major goal of fisheries science for both conceptual and management reasons. By examining the variability of 169 tuna and billfish time series of catch and catch per unit effort (CPUE) throughout the Atlantic as well as their linkage to the North Atlantic Oscillation (NAO), we find that the importance of these factors differed according to the spatial scale. At the scale of the entire Atlantic the patterns of variations are primarily spatially structured, whereas at a more... |
| Tipo: Text |
Palavras-chave: Time series analysis; North Atlantic Oscillation; Atlantic tuna. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-3984.pdf |
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| Registros recuperados: 13 | |
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