Oxygen isotopic composition of fogs and rains from the North Atlantic

1962 ◽  
Vol 18 (5) ◽  
pp. 222-223 ◽  
Author(s):  
R. Gonfiantini ◽  
A. Longinelli
Keyword(s):  
Isotopic Composition ◽  
North Atlantic ◽  
Oxygen Isotopic Composition ◽  
The North ◽  
Oxygen Isotopic ◽  
The North Atlantic

scholarly journals Reconstructing past atmospheric circulation changes using oxygen isotopes in lake sediments from Sweden

2009 ◽  
Vol 5 (3) ◽  
pp. 1609-1644 ◽  
Author(s):  
C. E. Jonsson ◽  
S. Andersson ◽  
G. C. Rosqvist ◽  
M. J. Leng
Keyword(s):  
Water Balance ◽  
Atmospheric Circulation ◽  
North Atlantic ◽  
Oxygen Isotopic Composition ◽  
Oceanic Circulation ◽  
The North ◽  
Oxygen Isotopic ◽  
The North Atlantic ◽  
The North Atlantic Oscillation ◽  
Circulation Changes

Abstract. Here we use lake sediment studies from Sweden to illustrate how Holocene-aged oxygen isotope records (from lakes located in different hydrological settings) can provide information about climate change. In particular changes in precipitation, atmospheric circulation and water balance. We highlight the importance of understanding the present and past lake hydrology, and the relationship between climate parameters and the oxygen isotopic composition of precipitation (δ18Op) and lake waters (δ18Olakewater) for interpretation of the oxygen isotopic record from the sediments (δ18O). Both precipitation reconstructions from northern Sweden and water balance reconstructions from south and central Sweden show that the atmospheric circulation changed from zonal to a more meridional air flow over the Holocene. Superimposed on this Holocene trend are δ18Op minima resembling intervals of the negative phase of the North Atlantic Oscillation (NAO), thus suggesting that the climate of northern Europe is strongly influenced by atmospheric and oceanic circulation changes over the North Atlantic.

scholarly journals Reconstructing past atmospheric circulation changes using oxygen isotopes in lake sediments from Sweden

2010 ◽  
Vol 6 (1) ◽  
pp. 49-62 ◽  
Author(s):  
C. E. Jonsson ◽  
S. Andersson ◽  
G. C. Rosqvist ◽  
M. J. Leng
Keyword(s):  
Water Balance ◽  
Atmospheric Circulation ◽  
North Atlantic ◽  
Oxygen Isotopic Composition ◽  
Oceanic Circulation ◽  
The North ◽  
Oxygen Isotopic ◽  
The North Atlantic ◽  
The North Atlantic Oscillation ◽  
Circulation Changes

Abstract. Here we use lake sediment studies from Sweden to illustrate how Holocene-aged oxygen isotope records from lakes located in different hydrological settings, can provide information about climate change. In particular changes in precipitation, atmospheric circulation and water balance. We highlight the importance of understanding the present lake hydrology, and the relationship between climate variables and the oxygen isotopic composition of precipitation ( δ18Op) and lake waters (δ18Olakewater) for interpretation of the oxygen isotopic record from the sediments (δ18O). Both precipitation reconstructions from Northern Sweden and water balance reconstructions from South and Central Sweden show that the atmospheric circulation changed from zonal to a more meridional airflow over the Holocene. Superimposed on this Holocene trend are δ18Op minima resembling intervals of the negative phase of the North Atlantic Oscillation (NAO), thus suggesting that the climate of Northern Europe is strongly influenced by atmospheric and oceanic circulation changes over the North Atlantic.

scholarly journals Modeling the Nd isotopic composition in the North Atlantic basin using an eddy-permitting model

Ocean Science ◽  
2010 ◽  
Vol 6 (3) ◽  
pp. 789-797 ◽  
Author(s):  
T. Arsouze ◽  
A. M. Treguier ◽  
S. Peronne ◽  
J.-C. Dutay ◽  
F. Lacan ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
North Atlantic ◽  
Continental Margins ◽  
Atlantic Basin ◽  
Exchange Time ◽  
North Atlantic Basin ◽  
The North ◽  
Geographical Variations ◽  
The North Atlantic ◽  
Nd Isotopic Composition

Abstract. Boundary Exchange (BE – exchange of elements between continental margins and the open ocean) has been emphasized as a key process in the oceanic cycle of neodymium (Nd) (Lacan and Jeandel, 2005a). Here, we use a regional eddy-permitting resolution Ocean General Circulation Model (1/4°) of the North Atlantic basin to simulate the distribution of the Nd isotopic composition, considering BE as the only source. Results show good agreement with the data, confirming previous results obtained using the same parameterization of the source in a coarse resolution global model (Arsouze et al., 2007), and therefore the major control played by the BE processes in the Nd cycle on the regional scale. We quantified the exchange rate of the BE, and found that the time needed for the continental margins to significantly imprint the chemical composition of the surrounding seawater (further referred as characteristic exchange time) is of the order of 0.2 years. However, the timescale of the BE may be subject to large variations as a very short exchange time (a few days) is needed to reproduce the highly negative values of surface waters in the Labrador Sea, whereas a longer one (up to 0.5 years) is required to simulate the radiogenic influence of basaltic margins and distinguish the negative isotopic signatures of North Atlantic Deep Water from the more radiogenic southern origin water masses. This likely represents geographical variations in erosion fluxes and the subsequent particle load onto the continental margins. Although the parameterization of the BE is the same in both configurations of the model, the characteristic exchange time in the eddy-permitting configuration is significantly lower than the previous evaluations using a low resolution configuration (6 months to 10 years), but however in agreement with the available seawater Nd isotope data. This results highlights the importance of the model dynamics in simulating the BE process.

scholarly journals Nd and Sr isotope compositions from the Gardiner Complex, East Greenland Tertiary igneous province

1993 ◽  
Vol 40 ◽  
pp. 280-287
Author(s):  
Troels F. D. Nielsen ◽  
Paul M. Holm
Keyword(s):  
Isotopic Composition ◽  
North Atlantic ◽  
Alkaline Magmatism ◽  
Sr Isotope ◽  
East Greenland ◽  
The North ◽  
Early Tertiary ◽  
Igneous Province ◽  
The North Atlantic

The Gardiner Complex formed during the early Tertiary opening of the North Atlantic. The complex is strongly alkaline and referred to a zone of alkaline flank magmatism 100 km west of the melting anomaly in the initial rift of the North Atlantic. Earlier investigations have documented that most rocks of the complex can be referred to three suites which are all suggested to have been formed from a single parental melanephelinitic liquid. The Nd and Sr isotope compositions presented here support this conclusion. Minor deviations are believed to be due to interaction with Archaean basement. The isotopic characteristics suggest that the alkaline magmatism originated in a source similar to that of the contemporaneous picritic and basaltic tholeiites. The isotopic composition of the source is Jess depleted than pervalent mantle (PREMA) and sets an upper enrichment limit to the composition of the Icelandic plume component 50 Ma ago.

scholarly journals Disentangling the effect of ocean temperatures and isotopic content on the oxygen – isotope signals in the North Atlantic Ocean during Heinrich Event 1 using a global climate model

2016 ◽  
Author(s):  
Marianne Bügelmayer-Blaschek ◽  
Didier M. Roche ◽  
Hans Renssen ◽  
Claire Waelbroeck
Keyword(s):  
Atlantic Ocean ◽  
Surface Temperature ◽  
Isotopic Composition ◽  
Sea Surface Temperature ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Sea Surface ◽  
The North ◽  
Heinrich Event ◽  
The North Atlantic

Abstract. Heinrich events are intriguing episodes of enhanced iceberg discharge occurring during the last glacial period and are characterized by a steep increase in ice rafted debris (IRD) found in North Atlantic cores. Yet, their signal is not directly recognizable in the carbonate oxygen isotopic composition recorded in planktonic foraminifera, which depends on both the prevailing temperature and isotopic composition of seawater. Using the global isotope-enabled climate – iceberg model iLOVECLIM we performed three experiments to shed light on first, the impact of the duration of a Heinrich event-like iceberg forcing on the North Atlantic Ocean and second, the mechanisms behind the simulated δ18Ocalcite pattern. We applied an iceberg forcing of 0.2 Sv for 300, 600 and 900 years, respectively, and find a strong and non-linear response of the Atlantic Meridional Overturning Circulation (AMOC) to the duration of the Heinrich event in iLOVECLIM. Moreover, our results show that the timing of the first response to the iceberg forcing coincides between all the experiments in the various regions and happens within 300 years. Furthermore, the experiments display two main patterns in the δ18Ocalcite signal. On the one hand, the central and northeast North Atlantic regions display almost no response in δ18Ocalcite to the applied iceberg forcing since the changes in sea surface temperature and δ18Oseawater compensate each other or, if the forcing is applied long enough, a delayed response is seen. On the other hand, we show that in Baffin Bay, the Nordic Seas and the subtropical North Atlantic the change in δ18Oseawater exceeds the sea surface temperature signal and there the δ18Ocalcite pattern closely follows the δ18Oseawater signal and displays a continuous decrease over the length of the Heinrich event with the minimum value at the end of the iceberg release. The comparison of the model experiments with four marine sediment cores indicates that the experiment with an iceberg forcing of 0.2 Sv for 300 years yields the most reasonable results.

Oceanic Evidence for the Mechanism of Rapid Northern Hemisphere Glaciation

1980 ◽  
Vol 13 (1) ◽  
pp. 33-64 ◽  
Author(s):  
W. F. Ruddiman ◽  
A. McIntyre ◽  
V. Niebler-Hunt ◽  
J. T. Durazzi
Keyword(s):  
Northern Hemisphere ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Local Source ◽  
The North ◽  
Land Mass ◽  
Oxygen Isotopic ◽  
The North Atlantic

AbstractThe oxygen isotopic stage 5/4 boundary in deep-sea sediments marks a prominent interval of northern hemisphere ice-sheet growth that lasted about 10,000 yr. During much of this rapid ice growth, the North Atlantic Ocean from at least 40°N to 60°N maintained warm sea-surface temperatures, within 1° to 2°C of today's subpolar ocean. This oceanic warmth provided a local source of moisture for ice-sheet accretion on the adjacent continents. The unusually strong thermal gradient off the east coast of North America (an “interglacial” ocean alongside a “glacial” land mass) also should have directed low-pressure storms from warm southern latitudes north-ward toward the Laurentide Ice Sheet. In addition, minimal calving of ice into the North Atlantic occurred during most of the stage 5/4 transition, indicative of ice retention within the continents. Diminished summer and autumn insolation, a warm subpolar ocean, and minimal calving of ice are conducive to rapid and extensive episodes of northern hemisphere ice-sheet growth.

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