scholarly journals North Atlantic subsurface temperature response controlled by effective freshwater input in “Heinrich” events

2020 ◽  
Vol 539 ◽  
pp. 116247 ◽  
Author(s):  
Chengfei He ◽  
Zhengyu Liu ◽  
Jiang Zhu ◽  
Jiaxu Zhang ◽  
Sifan Gu ◽  
...  
Keyword(s):  
North Atlantic ◽  
Temperature Response ◽  
Subsurface Temperature ◽  
Freshwater Input ◽  
Heinrich Events

scholarly journals Enhanced iceberg discharge in the western North Atlantic during all Heinrich events of the last glaciation

2021 ◽  
Vol 564 ◽  
pp. 116910
Author(s):  
Yuxin Zhou ◽  
Jerry F. McManus ◽  
Allison W. Jacobel ◽  
Kassandra M. Costa ◽  
Shouyi Wang ◽  
...  
Keyword(s):  
North Atlantic ◽  
Heinrich Events ◽  
Last Glaciation

scholarly journals Marine productivity response to Heinrich events: a model-data comparison

2012 ◽  
Vol 8 (5) ◽  
pp. 1581-1598 ◽  
Author(s):  
V. Mariotti ◽  
L. Bopp ◽  
A. Tagliabue ◽  
M. Kageyama ◽  
D. Swingedouw
Keyword(s):  
North Atlantic ◽  
General Circulation ◽  
Circulation Model ◽  
Global Ocean ◽  
Biogeochemical Model ◽  
Heinrich Events ◽  
The North ◽  
Heinrich Event ◽  
The North Atlantic ◽  
Marine Productivity

Abstract. Marine sediments records suggest large changes in marine productivity during glacial periods, with abrupt variations especially during the Heinrich events. Here, we study the response of marine biogeochemistry to such an event by using a biogeochemical model of the global ocean (PISCES) coupled to an ocean-atmosphere general circulation model (IPSL-CM4). We conduct a 400-yr-long transient simulation under glacial climate conditions with a freshwater forcing of 0.1 Sv applied to the North Atlantic to mimic a Heinrich event, alongside a glacial control simulation. To evaluate our numerical results, we have compiled the available marine productivity records covering Heinrich events. We find that simulated primary productivity and organic carbon export decrease globally (by 16% for both) during a Heinrich event, albeit with large regional variations. In our experiments, the North Atlantic displays a significant decrease, whereas the Southern Ocean shows an increase, in agreement with paleo-productivity reconstructions. In the Equatorial Pacific, the model simulates an increase in organic matter export production but decreased biogenic silica export. This antagonistic behaviour results from changes in relative uptake of carbon and silicic acid by diatoms. Reasonable agreement between model and data for the large-scale response to Heinrich events gives confidence in models used to predict future centennial changes in marine production. In addition, our model allows us to investigate the mechanisms behind the observed changes in the response to Heinrich events.

Were the North Atlantic Heinrich events triggered by the behavior of the European ice sheets?

Geology ◽  
2000 ◽  
Vol 28 (2) ◽  
pp. 123 ◽  
Author(s):  
Francis E. Grousset ◽  
Claude Pujol ◽  
Laurent Labeyrie ◽  
Gérard Auffret ◽  
An Boelaert
Keyword(s):  
North Atlantic ◽  
Ice Sheets ◽  
Heinrich Events ◽  
The North ◽  
The North Atlantic

scholarly journals Warming of surface waters in the mid-latitude North Atlantic during Heinrich events

2013 ◽  
Vol 28 (1) ◽  
pp. 153-163 ◽  
Author(s):  
B. D. A. Naafs ◽  
J. Hefter ◽  
J. Grützner ◽  
R. Stein
Keyword(s):  
North Atlantic ◽  
Surface Waters ◽  
Heinrich Events

scholarly journals Predictability of the Barents Sea Ice in Early Winter: Remote Effects of Oceanic and Atmospheric Thermal Conditions from the North Atlantic

2014 ◽  
Vol 27 (23) ◽  
pp. 8884-8901 ◽  
Author(s):  
Takuya Nakanowatari ◽  
Kazutoshi Sato ◽  
Jun Inoue
Keyword(s):  
Sea Ice ◽  
North Atlantic ◽  
Barents Sea ◽  
Temperature Anomaly ◽  
Early Winter ◽  
Subsurface Temperature ◽  
The North ◽  
The Barents Sea ◽  
Subsurface Temperature Anomaly ◽  
The North Atlantic

Abstract Predictability of sea ice concentrations (SICs) in the Barents Sea in early winter (November–December) is studied using canonical correlation analysis with atmospheric and ocean anomalies from the NCEP Climate Forecast System Reanalysis (CFSR) data. It is found that the highest prediction skill for a single-predictor model is obtained from the 13-month lead subsurface temperature at 200-m depth (T200) and the in-phase meridional surface wind (Vsfc). T200 skillfully predicts SIC variability in 35% of the Barents Sea, mainly in the eastern side. The T200 for negative sea ice anomalies exhibits warm anomalies in the subsurface ocean temperature downstream of the Norwegian Atlantic Slope Current (NwASC) on a decadal time scale. The diagnostic analysis of NCEP CFSR data suggests that the subsurface temperature anomaly stored below the thermocline during summer reemerges in late autumn by atmospheric cooling and affects the sea ice. The subsurface temperature anomaly of the NwASC is advected from the North Atlantic subpolar gyre over ~3 years. Also, Vsfc skillfully predicts SIC variability in 32% of the Barents Sea, mainly in the western side. The Vsfc for the negative sea ice anomalies exhibits southerly wind anomalies; Vsfc is related to the large-scale atmospheric circulation patterns from the subtropical North Atlantic to the Eurasian continent. This study suggests that both atmospheric and oceanic remote effects have a potential impact on the forecasting accuracy of SIC.

scholarly journals Enhanced iceberg discharge in the western North Atlantic during all Heinrich events of the last glaciation

2020 ◽  
Author(s):  
Yuxin Zhou ◽  
Jerry McManus ◽  
Allison Jacobel ◽  
Kassandra Costa ◽  
Shouyi Wang ◽  
...  
Keyword(s):  
North Atlantic ◽  
Heinrich Events ◽  
Last Glaciation

scholarly journals Export of ice sheet meltwater from Upernavik Fjord, West Greenland

2021 ◽  
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
North Atlantic Ocean ◽  
Atlantic Water ◽  
Water Masses ◽  
Buoyant Plume ◽  
Freshwater Input ◽  
The North ◽  
Freshwater Source ◽  
Lateral Mixing

Abstract Meltwater from Greenland is an important freshwater source for the North Atlantic Ocean, released into the ocean at the head of fjords in the form of runoff, submarine melt and icebergs. The meltwater release gives rise to complex in-fjord transformations that result in its dilution through mixing with other water masses. The transformed waters, which contain the meltwater, are exported from the fjords as a new water mass “Glacially Modified Water” (GMW). Here we use summer hydrographic data collected from 2013 to 2019 in Upernavik, a major glacial fjord in northwest Greenland, to describe the water masses that flow into the fjord from the shelf and the exported GMWs. Using an Optimum Multi-Parameter technique across multiple years we then show that GMW is composed of 57.8 ±8.1% Atlantic Water, 41.0 ±8.3% Polar Water, 1.0 ±0.1% subglacial discharge and 0.2 ±0.2% submarine meltwater. We show that the GMW fractional composition cannot be described by buoyant plume theory alone since it includes lateral mixing within the upper layers of the fjord not accounted for by buoyant plume dynamics. Consistent with its composition, we find that changes in GMW properties reflect changes in the AW and PW source waters. Using the obtained dilution ratios, this study suggests that the exchange across the fjord mouth during summer is on the order of 50 mSv (compared to a freshwater input of 0.5 mSv). This study provides a first order parameterization for the exchange at the mouth of glacial fjords for large-scale ocean models.

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